Such sites that do not allow Apple passwords I now skip as a user (unless it’s a government site), it says enough about how you view security and there are plenty of competitors that don’t do this
Not GP, but I had one just the other day that didn’t allow dashes in the password, but did require a special character (of a list of like a dozen, just not including dash). Also, it wasn’t that the dash wasn’t recognized as a special character, but that it wasn’t allowed at all. Wish I could remember what site now.