If they meant not to generalize the point, then at least for me they failed -- I would have liked to read it that way, but given the universal nature of the context they were describing, I had a hard time not seeing it as a general statement, or at least a very broad one.

"talking about being attracted to women, or writing porn about them, supports the Patriarchy" (noooo)

Yeah, that pretty much nails my issue with the thrust of this argument. I'm reminded of the bad old days, not so long ago, when people seriously argued that most female characters in mainstream media were so poorly created that the only properly "feminist" thing to do was to ignore them and write about the men. Fortunately we've (mostly) moved beyond that, but the undercurrent here is not so different.

...it doesn't explain why non explicit m/m romance and friendship is more popular than non explicit f/f romance and friendship.

Yeah. The particular debate I was following was focused on sexually explicit material, so that topic didn't really come up, but I agree that the broader question is just as important, and a much harder one to dismiss as personal preference a la kinks, sexual turn-ons, etc.