An in depth look at the characters
Why Rainbow Dash is clearly a villian
Rainbow Dash may seem like a nice, friendly pony just like the rest of the mane 6.
However, as an experienced brony who's seen the show many times over, I can safely say he is not.
Rainbow Dash is a villain, a cruel and malicious psychopath who pretends to be a good friend to the rest of the mane 6 so no one suspects that he's doing anything wrong. By day, he walks alongside his so called "friends" and feigns friendliness as best he can.
But by night, he goes on evil missions doing evil things with evil people.
Several things prove that Rainbow Dash is a villain rather than a hero like the rest of the mane 6.
As said by Applejack "A real hero doesn't brag". Which is exactly what Rainbow Dash does. He goes around bragging about all the epic things he does, being the selfish arrogant jerk he is and insulting others when he feels like it.
He has no regard for the safety or well being of his friends.
In "Trade ya" he was willing to sell Fluttershy just to get his daring do book. The very idea that someone would sell their friend into slavery over something so unnecessary like a book is clearly no true friend.
In "Super cider squeezy 6000" he wants Flim and Flam to take over Applejacks business just so he can get more cider. He only joined the mane 6 in helping Applejack so he could secretly sabotage their cider production process, making it go slower than it normally would if he wasn't secretly tampering with their efforts. He wanted Flim and Flam to run Applejack out of business.
- He cares nothing for his friends and picks on them without mercy.
In Dragonshy, this was especially true when he insulted Fluttershy.
In Dragon quest, he insulted Spike to no end, and traumatized the poor guy so badly.
In Hurricane Fluttershy, he poured boiling hot water onto Fluttershy, causing her serious pain. He cared nothing for her well being, and only cared for impressing Spitfire so he could join the wonderbolts.
In Rainbow Falls, he is willing to betray his friends just so he can fly with his "dream" team the wonderbolts. It was selfish of him to even think about doing such a thing.
- Not only is Rainbow Dash both arrogant and selfish and insulting towards even his friends, I argue that he does evil things as well.
I argue that...
In "Cutie mark chronicles" he sent the bullies to bully Fluttershy because he was sadistic and liked seeing Fluttershy being insulted defenselessly. Also, he only acted nice towards her so that he could later murder her. It was Rainbow Dash who deliberately pushed Fluttershy off the cloud with the intention of killing her, it was simple bad luck for him that a group of butterflies managed to save her from falling. In other words, he was the leader of the gang of bullies.
In "Somepony to watch over me" he sent the chimera to murder Apple bloom, he told the chimera that she would have a trolley full of delicious goods which it could have all to itself and told the chimera exactly which path Apple Bloom would take. It was simply lucky for Apple bloom that Applejack showed up in time to save her.
In "Ticket master" he didn't show one bit of regret over making Twilight so depressed.
In "Cutie remark" he refused to perform a sonic rainboom when Twilight begged him to, he knew it would screw up the future and thats why he refused to sonic rainboom.
In "Feeling pinkie keen" he attempted to assassinate Twilight several times by dropping various objects on to her. He also sent the swamp monster to kill Fluttershy, knowing she would be alone there. It was simply bad luck that Pinkie Pie had her pinkie sense handy, so all his assassination attempts failed. (he wasn't seen in the episode so that gives me the proof it might have been him who did all those terrible things)
In "Wonderbolts Academy" he got jealous of seeing lightening dust beat him, and so he decided once and for all to get rid of lightening dust. He created a giant hurricane, and saved his friends from said Hurricane not because he liked them or because he didn't want them to die (he did want them to die very much) but so that Lightening dust would get the blame for the hurricane and he would get promoted. Lightening dust refused to show much guilt for the hurricane because he was too angry at Dash for framing him for something he did not do and had no part in. He was put in jail for life for a crime he was falsely accused for, and till this day is still very miserable.
In "Tanks for the memories" he wanted the weather factory sabotaged not only so that he wouldn't have to say goodbye to Tank, but mostly because he wanted to cause mass destruction to equestria and pain to others. He wanted to kill all the Weather factory workers as well and if Tank hadn't done what he did, Rainbow Dash probably would have pulled it off successfully.
The equestria girls Rainbow Dash is just as bad as his evil pony counterpart
In the first movie, in my opinion, he was the one who broke his friends apart. Think about it, how much would Sunset Shimmer know about the Humane 5 compared to Rainbow Dash when he has spent much longer around them than she has. I mean come on, Sunset shimmer barely even talked to the Humane 6 (apart from stopping to insult Fluttershy every now and again) so how was she even supposed to know enough about any of their events to sabotage their friendship so effectively.
But now, think logically. As Applejack put it "the only person less trustworthy than Sunset Shimmer in this school is Rainbow Dash". Applejack probably didn't know it at the time, but what she said was actually very close to the truth. Rainbow Dash was less trustworthy still, and it would make sense for him to know his friends email addresses and when their events would take place because they would trust him enough to tell him all that.
In Rainbow Rocks, he refused to give his team any chance to shine in their song because he wanted all the fame and recognition for himself. He probably also made a pact with the Dazzlings when no one was looking, so that in exchange for sabotaging his teams chance to win, he would be allowed to rule the world with them when they won.
There are many other episodes where Rainbow Dash's evil nature is shown, but that's all I have time for at the moment.
Rainbow Dash in my opinion is nothing but an arrogant and manipulative psycho who cares only about himself and his own ego.
He's not above breaking rules and will gladly do anything to see others suffer in pain and agony. Though he is both selfish and arrogant, he is somehow still able to stay popular and on good terms with every pony in town. It is likely that he only joined the other members of the mane 6 and pretended to be their friend so that he could conceal the fact he was an evil criminal because of course, no one would suspect ponies as kind as the mane 6 to be guilty of anything bad.
Not much evidence is needed to show that Rainbow Dash is the worst criminal alive, worse than Starlight Glimmer, worse than King Sombra, worse than even Tirek.
One look at his arrogant personality and his bragging and lack of affection and loyalty for his friends says it all.