It's interesting that you view "not being a horrific racist" as a political alignment.
Either you're intellectually dishonest or you're not aware of Twitter's shenanigans over the past year where they'd allowed horrifically racist commentary like "white people must die" or anti-Christian commentary yet banned the accounts of white people who communicated even the lightest of philosophical questions on race or religion.
It's either all racist or it's not. It's either all anti-religious or it's not. Twitter became a selective judge and jury as to what constituted as racist based on the race and/or religion of the source and target.
Maybe they've cleaned up their act since the summer, when you could easily find #BlackLivesMatters quotes that literally cried for the death of white people or from other groups crying for Allah to kill people... but the damage is already done. Twitter's actions stated 'this is who we are, this is who we support, this is who we don't support.'
Explain how Trump exists so "bigly" on Twitter if it is such a rabid "SJW platform".
It's still used by celebrities, record labels, television shows, etc., to broadcast a message to the people that still effectively utilize said platform which, according to Edison Research last year, is 7% of the American population (which is what I assume you mean by 'bigly').
The explanation requiring the fewest assumptions is the most likely to be correct. -- William of Occam