I always hold women accountable for their inane comments. I will usually say something subtle but firm in order to indicate NOT my disapproval as much as the factual stupidity of her comment.
We as men need to hold women accountable for what they say and do, without fail. The whole reason we are in the mess we are in is because men have abdicated their authority and position of rational guidance.
Having said that, I will usually let some things slide in the heat of the moment. Interestingly, with my gf of 1.5 years, there hasn't been even one heated exchange. But with other women, depending on the circumstance, I might say, "i'll let what you said slide because it was in the heat of the moment", just to let them know I'm aware and judging what she says. We men should always cultivate a frame of judging everything she says, not the other way around. Once that dynamic is established, a man can loosen up and enjoy light, spontaneous conversation with her because she's learned to avoid pushing against your boundaries.
Have you guys noticed that in day to day observation, we can see a subtle dynamic of the woman judging everything about the man, even in casual conversation? We need to reverse that. I'm able to do it, and my life is a lot easier now because of it, and women respect me because of it.
You are a man. It is your privilege to judge every woman's words and actions within your sphere.
I think the "ignore it" school is dead wrong. It is possible to point out a woman's foolish or disrespectful words without appearing invested or ruffled. It is more like conveying surprise that a woman can be so foolish. Sort of a surprised amusement, with a dash of "how sad".