I haven't seen any particular bias against instrumentalists

My experience has been different. Especially on serious music threads about instruments that are often the subject of jokes. When I was a fairly new member, it was made very clear that it was considered bad form for people to BS around in serious music threads. But many people who subscribe to this rule of thumb don't honor it when the thread is about an instrument they don't take seriously, like the accordion. And when they talk about how they define "folk music", for many people the definition pretty much only covers songs with words.

Since the forum changed (a long time ago) to include instrumentalists, and since it is billed in the banner as being a forum for and about "folk" music and blues, it stopped being mostly about lyrics several years ago. But there do seem to be those who resent this change. And this is what I am talking about re: how one's experience here and how one defines "good change" vs. "bad change" will effect wheter or not one thinks the Mudcat has gotten "worse" or "better" in the long run.

One experience that still stays with me to this day when I think about this sort of thing was the thread started with a serious question about accordions that turned into a joke fest. And finally, one of the regular Mudcatters who plays the accordion told the original questioner that it would be better to discuss the subject of his/her serious music question in PMs rather than the open forum.