I respectfully disagree. I think it's extremely important to have discussions about various -isms in fiction. Fiction is a huge part of how we understand and view the world around us, and if our fiction has distorted worldviews, then we should know about it.
What I took away from that anecdote instead, is that tact is a thing and so is knowing what to say when, and that maybe charged opinions on tangential issues should be left to some occasion other than when your friend is trying to show you something that she worked really hard on.