First of all, note the order. It is based on rarity. Stupidity is common, while true evil is extremely rare.
I will start with crazy. Note I am using an emotionally charged word here, not a technical term. It makes for a clearer argument. I am not trying to insult anyone, nor make value judgements about any specific people. Just trying to use an extreme word for literary impact.
The hallmark of insanity is not believing false things. Lots of people are wrong about something. Nor is it their methodology/philosophy. Lots of people have different processes.
Believing you are President Obama does not make you crazy. In fact there is one person that believes he is President Obama and is totally sane - and correct. (i.e. the real President Obama).
Insanity depends not on facts, not on your philosophy, but on your reactions and conclusions.
Let's say there was some bizzare movie-esque plot to kidnap President Obama and give him plastic surgery so he doesn't look like himself. Upon awakening, he would not start insisting he is President Obama. Instead he gets a phone and makes a call and the Secret Service comes and get him. They check him over and quickly agree.
If you wake up thinking you are President Obama then the sane thing to do is to call the Secret Service, probably with some code word. If you try to do anything else,, you are crazy.
Same thing with just about every other kind of insanity. Extreme Germophobes are not crazy because they don't want germs on them. Nor are they crazy because they think that germs are everywhere. They are crazy because of the extreme reaction to these facts and philosophies. Their desire to obsessively clean everything is what makes them crazy.
Note, insanity is at heart not something sane people can understand. We don't say "Why yes, I might do that if I had different ethics." It is illogical and incomprehensible to sane people.
Also note, that just because you are crazy, does not mean you are stupid - but it also doesn't mean you are smart. Similarly, being crazy doesn't mean you are evil and it doesn't mean you are good either.
As a result, while crazy is relatively common, it doesn't spread. In a set of 10,000 people, there may be a lot of 1,000 crazy people - but they won't agree with each other.
Next comes evil. Evil can be quite logical and have reasonable reactions and conclusions. It doesn't have to be crazy. Nor is it by default wrong as to facts. You can be totally correct about a situation and still be evil.
Evil is about the methodology and philosophy that you use. If you see a bank, recognize it has money and that the money is not yours, then non-evil people will accept that and leave it alone. But if your philosophy says that it is OK to take things that aren't yours that you want, then you would steal the money. You would do so because you are evil, not because you are crazy.
Evil is something people can understand. We know full well what we might do if we had different ethics/philosophy.
Which is why true evil is so relatively rare. You see, you don't have to be a genius to recognize the value of some one else's philosophy. You just need a genius to create the philosophy/ethics. Then the average guy can usually see the advantages of the better ones, adopting them and abandoning the ethics and philosophies that don't work so well. Sure, some people will stick to less efficient ones, but over time, the better ones tend to survive, while the worse ones die out.
Evil, unlike crazy, does spread. If everyone else is stealing, then it encourages other people to steal. Luckily, it is relatively rare. In a set of 10,000 people, there may only be 100 evil people - but they will all agree with each other and can work together (i.e. organized crime, politics, etc.)
Finally lets talk about stupid. By stupid, I mean getting facts wrong - and/or not using reasonable methods to check them. When you think the Earth has only a circumference of 30,200 kilometers (Columbus' estimate) when in fact it is 40,000 kilometers, you are wrong.
It's not just getting the facts wrong, but your method of checking them. Columbus just looked up the Abu al Abbas Ahmad Ibn Muhammad Ibn Kathir al Farghani, aka Alfrangus work and failed to realize that a Alfrangus, being Persian, used an Arabic Mile, rather than a Roman Mile.
Stupid is common. You have to judge facts for yourself. Philosophies get tested repeatedly, and learned over years. Facts often just get accepted. Which means stupidity spreads like evil does. In a set of 10,000 people, there may be 3,000 stupid people. And they will all quickly agree with each other.
Now, lets' talk about the situation as a whole
When I agree with your facts, your philosophy, and your reactions, I agree with you.
When I disagree about your facts, one of us is wrong - and possibly stupid.
When I disagree about your methodology, one of us is evil.
When I disagree about your reactions, one of us is crazy.
Crazy doesn't think that well, and doesn't cooperate. It can't gang up or join with stupid or evil.
Evil has long ago figured out that the rest of the world thinks it is evil and hides it. Sometimes it gathers stupid to do it's dirty work.
Stupid tends to put forth their stupidity and doesn't understand why other people ignore them. Stupiid also keeps thinking people don't understand them.
A good example of this is the 'white power' movement. It is evil and has gathered stupid to it. The stupid make ridiculous claims that other people instantly see through ("We are just an equal rights movement for whites") Stupid, being easily fooled by simple lies, puts forth it's own stupid lies that are easily seen through.
Stupid often surrounds it's false facts with huge number of true ones, always shown first. If someone gives you a list and the first stuff you agree with, then the later stuff seems questioanble, they put it in that order on purpose. They want you in the habit of agreeing with them by the time they start feeding you bull.
Similarly, evil likes to start out by feeding you a bunch of facts, that you agree with then, then move on to a questionable situation, ending in a false evil philosophy.
Just because someone is right about one thing doesn't make them right about anything else.
You can also agree with someone's facts but object to their philosophy - or reaction/conclusions.
That is, yes, I can agree that most of the prisoner's in the US are black, but I know that is due to poverty that correlates with race, not genetics. Similarly, I can state that most prisoners are male, but that does not mean women are ethically superior.
It also works the other way around - I can believe that sex abuse is a horrible, despicable crime but I can also know that people arrested for sexual crimes are far LESS likely to commit any other rime than someone arrested for violent or money based crimes. Sex crimes has recidivism rate of only about 5.3%. (source).
Yes, most people have this fact backwards - they think perverts that get caught are sick and will repeat. They are wrong. Mainly because they think 'sex crimes' refers to psychotic child rapists that kill then eat their victims, not random drunk people arrested for peeing in a school yard (guess how many people on the sex offenders list come from which of those categories).
Do not let the evil and stupid people trick you simply because they begin their discussion/argument with true facts.