oldhatemachs write-up is inaccurate. 4chan isn't what it is because it's a magical place of anonymity where your opinions are considered in a vacuum. 4chan is what it is because, as time goes on, the website attracted the people that were getting banned from pseudonymous websites. As these kinds of people accumulated and accumulated, the website became progressively more toxic in every way, which drove out people who didn't enjoy that, which gave the most toxic members hegemony.
It's also not true that 4chan has stopped doxxes and raids. Just yesterday /pol/ was full of people that were scouring everything they could to doxx the security guard involved in the shooting. 4chan was also counterraiding the leftist bunkerchan to have revenge on them making a meme about the facial features of the kind of people that enjoy /pol/.
And it's also wrong that 4chan is a paragon of free speech. It used to be, but as the userbase started harboring more and more fascists, and as more and more of them became janitors, they started censoring leftist posters unless they refrained from, well, anything that makes a Chan a Chan.
4chan in general is also highly resistant to evidence that goes against their narrative, and won't shy away from accusing the authors of any study they disagree with of being part of a Jewish conspiracy.
Most of all, the biggest meme in that post was calling /pol/ "slightly grown up from their libertarian idealism, [...] now with a hint of conservatism". /pol/ is openly fascist. As in, Julius Evola, Swastika, Black Sun, genocide, kind of fascist.
People who spend their time talking about the day of the rope being censored isn't what drove them to violent tendencies, what drove them to violent tendencies is a mix of being socially recluse, racist, white males, egged on by literal Nazis who saw the opportunity to radicalized them, all of that in a community so repulsive to anyone else that few enjoy being there.
It's not even that creative either. The main mascot of /pol/ was stolen from some random webcomic, the wojak came from Krautchan, and so on. It's just slight memes from someone else's art and a few puns. It's not a main creative force of the internet, far from it.
Those are the dynamics behind 4chan becoming what it is. Purely anonymous websites in a pseudonymous majority will inevitably become a disaster. That poster is someone who was carried down the rabbit hole and can't realize just how extreme and wrong their opinions are, who can't realize what their values became, trying to convince themselves their worldview and website isn't as insane as it is.