Well if he doesn't know the difference between "your" and "you're" ...
Did I miss something? All I saw was that text message you posted that talked about his gf's anxiety. I didn't see anything that was that crass or basic in the exchange.
The other factor is "happy wife, happy life" may also apply. He may know or have witnessed her anxiety causing relationship issues in the past and would rather err on the side of caution. Sometimes avoiding anxiety-triggering situations is a good way to deal wth anxiety.
Onwards and upwards...
"... expressed preferences for male bandmates..." and "nothing to do with your playing, we thought it was good"

