I've never seen an ISP block usenet. I've seen ISPs stop hosting their own free Usenet servers, but that's not blocking Usenet. I'm searching for an adequate s

I've never seen an ISP block usenet. I've seen ISPs stop hosting their own free Usenet servers, but that's not blocking Usenet. I'm searching for an adequate source for this information but I'm failing to find anything to stand on its own. It's definitely been treated like common carrier for many years, but as for an official classification... I'm struggling to find one.