I downvoted you because this is a ridiculous claim. If you use a platform like Gab that embraces bigots and extremists perhaps, but that's not the only other platform.
Edited to clarify my opinion that only one of these two claims is ridiculous
You have to realize that most things can be viewed as bigotry and extremism. Look at how feminism and lgbt are viewed around the world - as extremism. Would you say twitter "embraces" bigotry and extremism because they allow feminism and lgbt on their platform?
It's a question about monopoly and fairness and the cultural values of america. Free speech is both a legal and a cultural concept.