Okay, now that I'm less tired, a more salient point:
Opt-out is not "you haven't consented," opt-out is "we have a situation where there is generally consent and we are giving you the ability to _revoke_ that consent."
For instance, if I'm setting up a mastodon server, the fediverse has a _generally granted consent_ for me to do the things a normal mastodon server does, but they also provide a(n imperfect, more on that some other time) mechanism of consent _revocation_: blocking.
1/