You can rail against suppression of speech all you want, a company whose loudest and most active users are white supremacists either has to lean-in to that culture, remove it from the site entirely, or hide it. The first option is moral bankruptcy, the second option is an uncomfortable practicality on the limits of free speech, and the third option makes your new site look dead from the outside.
You act like this is a simple problem to solve, but it's far from simple, and getting it even slightly wrong means startup death, period.
In a free market, the majority of people would not entertain far-right or far-left forums and would congregate on the services which are providing engaging and meaningful content.
This is the case for say, Youtube right now, but if they have an asymmetric approach to censorship (failing to ban far left ideologues), then they'll end up a far-left cesspit that people will leave in droves.
I care very deeply about fundamental human rights such as free speech. Many people do not seem to understand what free speech is.
I also care about due process and putting people before a jury of their peers. The witch hunting needs to stop.
I'd consider myself moderate right. I used to lean to the left, but there is no way I can associate myself with what the left has become.
I'm with you on free speech, but I also don't know what I'd do if I were in Twitter/Reddit's shoes, because I don't think "do nothing and let the hatred continue" is viable (both from a business and kindness perspective), but I also don't think suppressing it is morally justified.
The divisions are only getting wider, and it is helpful to neither side. When people say racism is on the rise, they couldn't be more correct. White-racism is on the rise, and tolerated. The increase in white supremacists I see as largely a reaction to this. I'm not a selective racist and I despise racism in all of its forms.
Sexism too. Sexism against men is also very real, especially in tech. A diversity quota is a sexism quota. A person's gender should not factor into a hiring decision at all.
Every new social media company is basically planting their flag very far in one direction or another (either blocking hate speech or leaning in entirely).
The best thing for people to do is reject both this idiocy, and the idiocy of the far-right which wants to revert things back to the old way. This is what the people in the IDW are aiming to achieve - to bring people back to having discourse rather than bickering and widening the polarisation.
We have racists and sexists on both the left and right. We need to denounce racism and sexism in all of their forms, else the problem is only going to increase
A free market would (and does) kill a startup that allows such toxic members of any affiliation, regardless of what payment processors decide to do.
And the reason "alt-right" and "racist troll" mean nothing is because they are used so liberally where they do not apply, and a few minutes of investigation would conclude that they do not apply. Consistent incorrect usage of language applied to something that it is not makes them lose their meaning.
A solution to the "adhering to free speech" would be to allow free speech on platforms, and make it clear what is or isn't allowed on the platform, instead of using vague terms like "hate speech", which could be literally anything that some person finds undesirable.