You probably have Verizon - they've started null routeing traffic to sites "like this".
https://old.reddit.com/r/mangadex/comments/nvj7qf/is_verizon...
https://old.reddit.com/r/mangadex/comments/nvj7qf/is_verizon...
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.
That's disappointing. If only I had some choice to ISPs, then I could express my disappointment by voting with my wallet…