I have the same experience as you and wondered if GP (green account at the time of writing) was trolling. Their other comments seem reasonable though. Based on those, I'm guessing their issue might be compatibility. (Still a flippant and useless comment in isolation, though)

I've not had any issues myself (all players I use supported it already once I learned of Opus' existence about six years ago), but GP doesn't seem to be the only one in this thread. Platforms like youtube don't seem to have an incentive to switch, everyone wants to be compatible with them and they'll re-encode uploads anyhow