That would put the burden of verifying the identity of users on the website operator before they can participate. Personally, I know I don’t want to have the responsibility of handling PII just so that a stranger on the Internet can participate on a public forum where there could be harassment when I think we’re doing a good enough job by moderating the platform with a decent set of rules.
And this kind of requirement doesn’t really consider the nature of a federated platform such as the fediverse, as I couldn’t vouch for the identity of remote instance users if we get audited.
Technically, a torrent is downloaded in blocks, so it’s more like