The website has the right to choose when you can use it unfortunately. If you don't like the decision, don't use it. Or you could just use a content blocker if the cookies are the issue.
It's not their business to know or dictate how to use my browser. It's like they were telling me I can only browse their site while wearing pink socks or something.
I forget but you can see the urls on the screenshots.
I just prefer to have permanent private mode. Mobile Firefox is frankly pretty crappy and bloated, and it just works better when I don't need to deal with cache and cookies and shit. And I can still use pwas like for Lemmy.