Yeah, one of the weirder things is that if someone blocks you, you are not allowed to reply to any comment in the thread (for example, if someone posts a toplevel comment and doesn’t reply to anything, and you reply to some comment a dozen layers below and have an exchange with some third party, if the toplevel commenter blocks you, you can’t reply to anything including comments left by others in response to your own comment) and you get a generic “internal server error”-type pop up with no information about why the request failed.

This is most likely a server “feature” and thus a rewrite of the frontend won’t fix it but it seems like at very least the frontend could display a sane error message (assuming the backend forwards some information about the cause of the error).