If I walked into a local bookstore and saw a whole shelf dedicated to white supremacy, I would rightfully be appalled that it was allowed to exist, because stocking such books would reflect on the bookstore. The Internet is like a bookstore where anyone can write a book and guarantee it's stocked, and free to read, and therefore completely unlike a bookstore at all. Yet we tend to think of online discussion platforms in these terms because the idea of a true online free speech platform where only content that is Actually Illegal is taken down and reported to the authorities accordingly is still incredibly foreign to us at a societal level. Someone who's never used the Internet and never met any (for example) white supremacists in their lives may go online for the first time and see an active discussion among white supremacists taking place, and this causes cognitive dissonance: "I've never met a single white supremacist in my life, yet here's dozens of them, virtually congregating and discussing their racist viewpoints! What the hell is happening? Is the Internet full of racists?" Humans are terrible at comprehending numbers on the scale of "the number of Internet-connected users in the world," so it's hard to understand "the proportion of vocal white supremacists online compared to the total number of people using the Internet in the world is just about as small as you previously thought it was" when they're given the same equal voice as everyone else.
There's no easy solution to this. Unless a massive societal shift in understanding how the Internet works and fits into modern human society happens, "safe" yet censored platforms like Twitter will always be more popular with normal users compared to "true free speech" havens like Gab, and generally-offensive extremist viewpoints will congregate on services like the latter after being kicked off of services like the former, making services like the latter a hard sell to people who don't hold extremist viewpoints themselves, in spite of the promise of unrestricted free speech.
It's been wild seeing the increase of people openly advocating against unfiltered free speech on the Internet as the Internet has gotten popular with the rise of smartphones, to the point where some people seem to consider "free speech" a "talking point" or "dogwhistle" of "the other side."
Until the singularity happens and we become one global consciousness and ascend to a higher plane of being, we're never going to have uniform beliefs as individual members of our species, and people with offensively extremist views will always exist. Silencing their views on a given platform out of a sense of righteousness and justice may feel good but solves nothing. You cannot change peoples' minds or eliminate ideas by making them illegal or against platform policy to express. Once you acknowledge and internalize this, browsing the Internet and occasionally coming across extremist opinions becomes a lot easier to grapple with.