Ah shucks I thought we had mostly avoided that stuff in the US.
I'm guessing though they're using some old spam ip/block though, there's a lot more obvious piracy sites then a Manga site. For instance, I can access all the major torrent sites.
They also block nyaa, an Anime/Manga focused tracker. It's not a very aggressive list though, as you're right that major torrent sites are still accessible.
https://old.reddit.com/r/mangadex/comments/nvj7qf/is_verizon...