They pay people to do that.
https://www.similarweb.com/website/news.ycombinator.com#over...
Edit: 147M in September.
Edit 2: I'm talking about page views, plus ajax requests like collapsing subthreads. If by 'visits' you mean user sessions, that number would obviously be lower.
>Traffic by countries
>United States 36.66%
>China 13.19%
According to that data, it started in August, which is also when people started to notice: https://news.ycombinator.com/item?id=20599249
(Edit: just noticed you were in that thread. I think it was the first; at least I can't find any others with this search: https://hn.algolia.com/?dateRange=all&page=0&prefix=true&que... )
The block doesn't seem to be absolute, as some of GreatFire's servers still occasionally get through. Based on previous experience, I guess it's location-dependent, but can't say for sure.