This discussion has slightly been done to death but I agree to an extent that "I do think the idea (that we can't tell) deserves to be mocked. In fact I think one reason why we're in this mess (and I posted this on the thread) is arguably that we didn't mock the idea early enough or loudly enough and now it's gained traction."
I think replace 'mock' with 'point out that it is factually incorrect' is probably more successful because the very hard-of-thinking (and there are many. Far more than you could ever imagine) pretend that it is appearances being mocked, not the idea. So yes, we have to put the work in to separate that but there really isn't much sensible discussion to be had otherwise. AND I think we have to be careful not to create another atmosphere where jeering at what people looks like in general becomes common, because that is usually used to make women feel awful about themselves or question their right to say something. (Just thinking about that senior police officer in her dress. How tf did that even become anything anyone commented on?)
"It's ill thought out and appeals to the lowest common denominator. It's not trying to engage in a wider more nuanced debate on this, although it may lead to others doing so. It appeals to a certain section of the population who don't want those type of discussions." I agree, and I think the people for whom that matters probably aren't going to change their thinking anyway.
Also, I still disagree that we know for a fact that we can always tell someone's sex, because we only can tell the ones we CAN tell! I am sure that the number of people we can't tell their sex is very very low. But I for one have encountered such a person (on TV) - I think it's more common with female people than male.
But posting stuff like this on another thread led to me getting yelled out and lied about, so frankly I can't really be arsed getting into it again, so apologies for anything you don't agree with, and as always - [disclosure for those who think someone's appearance changes the validity of their argument - my hair is a right mess and I'm wearing awful novelty socks)