Interesting! The first time I saw myself in heels - in my case chocolate brown knee boots with five inch stiletto heels worn over skinny jeans - I was unsettled. Not horrified, but definitely unsettled. It felt very strange to see myself in stilettos. Rather than get all self conscious about it, as I might usually have done, I studied what I saw and I realised that was unsettling about it was not that I looked bad in heels but the unexpectedness of it, the femininity of them as counterpoint to the rest of me.
Considered dispassionately I did not look bad in stilettos. My legs are slender from being generally fit, and if one was to see an image of just my legs, from the thighs down, one would have made an assumption that it was a picture of a woman’s legs in high heels. It is only when one sees the male top half that the unsettling bit comes in.
My conclusion is that men do not intrinsically look bad in heels - it’s just that it is unexpected, contrary to the norms and therefor unsettling. The more it is seen, the less unsettling. And perhaps the more minds open to the idea that men can look good in heels.