A challenge to Twitter? Bwahahaha, you're hilarious
Some gems just from wikipedia -
'Gab has been described as a platform for white supremacists and the alt-right'
'The site has been described as a favorite of alt-right users who have been banned or suspended from other services'
'hate-filled echo chamber of racism and conspiracy theories'
Yep, sounds like a real contender.
And of course this is the problem
"Social Media" is seen by many as just that. A game everybody can play.
As a consequence many people believe (Incorrectly) that what they see on social media is broadly representative of the points of view held by the general population across the political spectrum.
Unfortunately, this isn't the case, they are private corporations with their own terms of service. Sure, As such they may well have the right to decide which views are permitted and which are not.
But it is a very dangerous right to exploit.
By choosing to exclude certain POV, the mainstream media is presenting a distorted image of what the general population might actually feel.
It also means that alternative social media organizations will arise to fill the void, which will also end up presenting a distorted image of reality (See Echo Chambers)
On balance, I believe it is healthier to allow all views to be expressed.
(And this applies to government legislation as well as the T&C's of private organizations)