If you don't understand that free speech is like every other right in that it is not absolute, and does not apply to private platforms - then you should have paid more attention in your middle school civics class.

Gab is a cesspool of hate speech up to and including people using it to advocate things like treating Jewish people like livestock, holocaust denialism, and being used to coordinate conspiracy theories and harassment of innocent people and individuals

https://en.wikipedia.org/wiki/Gab_(social_network)