It isn't. We know this because there was a time before xcancel and people just accepted they needed an account.
It can happen - nobody would post an Instagram link to HN. But for X it did not happen.
Notice the EU's Digital Markets Act is a liability shield for Nitter instances hosted in the EU.
That assumes the people who need XCancel most are aware of its existence, but from what I can tell only folks like us are.
In the time before xcancel, nobody was aware of xcancel, that's correct.
Nitter existed well before Twitter first experimented with requiring a login wall to read posts.
People used it because it provided a lighter, cleaner interface, because it avoided Twitter's user tracking, and because it was reasonably useful without Javascript.
(I don't disagree that X has moved beyond the pale, but Nitter was a real boon in the past)