On the one hand, it seems noble/responsible to suppress anti-vax, Russian influence, conspiracy theories, etc.
On the other hand, for centuries it's been recognized that the best antidote to "bad speech" isn't censorship, it's more speech. Don't ban, convince.
But on the other other hand, that's been exclusively argued in the domain of government action, that government censorship is ultimately worse than what it purports to cure.
In this case, tech firms/platforms like Facebook, YouTube and Pinterest aren't the government or society, they're private actors just like newspapers and members of the free press in general. Just like it could be irresponsible of the NYT to publish letters to the editor supporting anti-vax, you can argue it's equally irresponsible for tech firms to allow the same on their platforms.
Yet on the other other other hand, we're reaching a point where a great deal of discourse is concentrated on a few user-content-driven sites, so censorship on them feels like it's inching closer in spirit to government censorship.
But on the other x 4 hand, mainstream public conversation has always been driven mainly by merely a handful of newspapers and then news programs with their own editorial agendas, so a handful of tech actors exercising their own "responsible" (as self-interpreted) curation and promotion doesn't seem to be anything new.
In the end, free speech has never been an absolute right (e.g. yelling fire in a crowded theater, libel, etc.) and it's ultimately a question of finding the right balance between harms.