Re: Their ideo of racism is probably different from yours...
I will defend your right to have a different opinion and say it even if i disagree with it.
A very fine sentiment and one I agree with in principle, but no Law forces you to share your megaphone at Speakers Corner with that Person who's opinion you disagree with. And thats all twitter is - A Megaphone on Speakers corner. By taking away that megaphone, you are not stopping that Person from shouting out their views even if they can no longer reach the same number of people. You are not violating their rights to freedom of speech. They can still create a Website and espouse there views there. They can create their own twitter like App if they're dedicated or go and use one of the dozen of other alternatives that exist to Twitter. And they do exist. They may not have the reach of twitter, but they are there and they are options.
Twitter feel their brand and their ability to make money is being harmed, so they are entitled to take their megaphone away and only let the people they want to use it. That's Twitter's choice, they spent the money to develop the program, they can do with it what they want. If their choices, make the platform undesirable, People will vote with their feet - remember myspace? Second life? geocities?
Twitter have made the call that extremists who call for violence or celebrate violence have no place on their megaphone, it's their call to make. Free speech is not impinged here, just the belief among those who spout support for violence that they have a god given right to spew their bile from whatever Megaphone they wish. Hopefully, this might cure them of this Notion. but i doubt it.