IIRC you can’t even read a single post without an account, it is equivalent to posting a link to a private Facebook group or whatever from an outsider point of view.
You can see the last few posts of an account [1], and the contents of a single posts, but minimal or no comments [2]. Videos play after dismissing the login popup.
What's difficult is reading threads, or more broadly replies. But single posts? Absolutely fine, in fact it's about the only thing that is totally functional without being logged in.
Oh, weird. I didn’t think there was a way to get rid of the pop-over that hides the post on iOS Safari. But it turns out that there’s a button to close it, just, completely disconnected from the pop-over and hanging out with a bunch of unrelated UI.
They changed this slightly, and 1-3 “top” comments are now sometimes visible, but you can’t dig into the thread. And if you click anything you get popups asking you to log in.