Just pick one, you’re thinking too hard. I just picked one that’s open because I didn’t want to write an essay about myself to prove my worth and get someone to accept me, because I know that there isn’t any reason why anyone would accept me over someone else (I’m a nobody). I hate the idea of someone else having to review my worth before being allowed to sign up, what a disgusting concept. “Oh it’s to stop spam 🤓” All the other sites have been dealing with Spam good enough without asking me to prove my worth to them, maybe the Fediverse should take some pointers from the big boys at Big tech, they seem to be doing better than you are when it comes to this.
Your example with YouTube is not an anti-spam measure, it’s them trying to restrict and create exclusivity with their content, they’re just lying and calling it anti-spam. I think it’s better to have some annoying automated spam defense like Reddit and the gang does than it is to be judged on my worth and denied because I’m not interesting enough or meet some dumb criteria to join the exclusive clubs Lemmys are slowly becoming fuck that.