Big tech should be doing so, but they already get pressure from advertisers to moderate that away. For the smaller ones like the insane right winger sites, let them spew nonsense, since it sets a dangerous precedent for everyone else if they’re not allowed to shit out misinformation and bigotry.
That’s where the internet should very much be made free. There’s too many cases of legitimate websites that can be shut down through these means. We need to correct misinformation with correct information.