It's a mixed bag. Initially there was fear that 'deplatforming' would make these ideas stronger, and the people promoting them 'martyrs' and their 'martyrdom'

It's a mixed bag. Initially there was fear that 'deplatforming' would make these ideas stronger, and the people promoting them 'martyrs' and their 'martyrdom' a 'cause célèbre' that would promote them even further. In other words, that the Streissand effect of deplatforming someone would make them more powerful. Reality seems to contradict that. People who used to enjoy quite a bit of notoriety a couple years ago have essentially disappeared since being deplatformed. Idiots like Milo Yiannopoulos, Gavin McInnes, Alex Jones and a whole bunch of other alt-righter 'personalities' who promoted white supremacy, homophobia, xenophobia, etc. have lost their audiences and are only recognizable by a handful of people who were aware of their positions before they got deplatformed. On the other hand, the people that put the effort to continue following such personalities and ideologies in whatever platforms they managed to stay on, belong to the extreme fringe of the original audience. Because the platforms that still host these people tend to host all kinds of terrible stuff, it's possible that some are being exposed to bad views they didn't espouse before. But let's face it: anyone digging through white supremacist sites to get the latest from Gavin McInnes was a lost cause anyway. In conclusion: deplatforming seems to limit exposure of new people to such perspectives, without requiring government-enforced violations of the First Amendment. There's nothing we can do against people actively looking for such anti-perspectives, because they are already biased against the 'normal' perspective. Conspiracy theorists have existed forever, but only recently they've become mainstream and affect public policy.