Welcome to the forum! The talk of Facebook groups reminded me of a chat channel we had in work. I work for a very big company with thousands of employees, and before we shifted to MS Teams, we had active channels for various interests. One of those was for musicians, and people would talk about guitars, how they practiced, where they played, etc. One guy on there was so opinionated about everything and I'm sure wound up a few more people than just me. Then someone asked him what instrument he played. Turns out, he didn't play anything, wasn't learning to play anything, didn't compose or do anything remotely related to making music. So yeah - one of those "experts".