I think the poster is referencing that uBlock Origin does not work with browsers other than Firefox. And that while some sites work poorly (deliberately deprecating Firefox), other sites work very poorly (without uBlock Origin). Presumably spoofing user agents works for now but has its limits.

What!? This thread is about "unsupported browser(s)", not anything that uBlock Origin fixes.

For what it's worth. I agree with OP which is why Firefox with uBlock Origin is my primary browser.