They always let anyone publish a paper, as long as the submitter has an email address from a known institution OR an endorsement from someone who does. Any edu-email may actually suffice if I'm not mistaken.

yes that's the whole point of arxiv to allow anyone to publish.

arxiv.org is not a peer-reviewed publication but an archive of scientific documents. Notably, it includes preprints, conference papers, and a fair bit of bachelor's and master's projects.

The best way to use arxiv.org is to find a paper you want to read from a "real" publication and get the pdf from arxiv.org so you can read it without the publication subscription.

That is not to say arxiv.org is all horseshit though. Plenty of good stuff gets added there; you just need to keep your bullshit radar active when reading. Even some stuff published in Nature or IEEE smells like unwashed feet once you read them, let alone what arxiv.org accepts.

Good citation count and decent writing are often better indicators than a reputable publication.

The exact same thing happened with crypto and "whitepapers". I think it's because both these fields have so many grifters that believe an arxiv paper provides them much-needed legitimacy. A blog post doesn't have the same aura to it...