Some friends of mine recently visited Temple Square and struck up a conversation with a sister missionary. She asked my male friend where he served, and he responded that he hadn't. She was shocked and kept insistently asking him why he didn't serve a mission. He kept politely evading her questions, and she wasn't picking up that he didn't feel comfortable answering. The reason he didn't want to answer was that the answer was that he was gay and wasn't allowed to.
I imagine that his guess was that if he answered her truthfully, then she would be dismissive and not give proper respect to his situation. She might tell him that with enough faith/study/prayer/fasting he could someday go on a mission, or that even his "same-sex attraction" was a temptation that the Lord would help him with.
If he had answered her, and she had responded like that, I think it would have been absolutely acceptable to call her out.
Most often I stay silent when I could be assertive, and I usually let other people dominate conversations. Many times I just assume that if I and someone else have different opinions, then the other person's must be the right ones. But I'm realizing more and more how many times it would be completely appropriate to be more assertive. The freedom of saying what I really think, politely yet firmly, makes me almost giddy. This is the way the conversation would go in my head:
-But why didn't you go on a mission?!
-I'm gay and I wasn't allowed to.
-[Noticeable pause] Well, I know that Heavenly Father will help you with this trial. Just stay close to Him, study his words, and pray sincerely.
-Actually, it's not a trial. It's part of my identity, and it's not going away—no amount of prayer and scripture reading is going to make it go away. That's a false idea that's perpetuated by well-meaning members, but it's not true.
I think it's alright to be direct. It's one thing if you're being unnecessarily harsh, but if you are being passively/backhandedly criticized, then you deserve to defend yourself.
By the way, I don't disagree with my friend's choice to not answer—I support him in his decision. I'm just saying that had he decided to answer a different way, he would have been justified.