I’m not sure whether it’s that, or that simply no one wants a platform everyone isn’t already on.
Personally I would absolutely not mind being “harassed” by text, if I was also able to exercise wide spectrum of free speech myself.
A social media platform advertised as a politics-first/free-speech platform is the social media equivalent of a beer ad featuring a divorced balding man at last call in a dingy basement bar. No one aspires to bicker about politics with strangers on the internet, even though in reality that's the engagement that pays the bills.
This is quite a controversial statement.
This is precisely the idea behind 4chan.