In a world where nobody was shamed for their weight, would you still feel insecure about it? Or is it maybe that your insecurity is based on external expectations you're afraid you can't meet, regardless of whether someone has explicitly mocked you for it?

Edit:

Also, if nobody has mocked you for it, then either a.) you're not in the demographic that is actually affected, or b.) female body positivity is working. And if it's b, then why not extend the same courtesy to men who don't fit the conventional beauty standard instead of telling them their trauma is their own fault?

My point here is that the way society treats people matters. 20 years ago women who wore something above a size 6 were made to feel horrible about themselves. Eating disorders were rampant. But thanks to a concerted effort to push more realistic beauty standards, women who are not rail thin do not feel the need to hate themselves by default. We live in an age where someone like Lizzo is celebrated, not reviled (recent revelations notwithstanding).

At the same time, male beauty standards have become significantly less realistic. 6' is a commonly cited minimum height, when only 15% of men are that tall and the "average" physique is mostly only attainable through use of steroids.

I'm 100% on board with the women's body positivity movement. I'd like to see something similar applied to men as well.

I think it's implied in the claim that the insecurity is purely internal and not based on how short men are treated.

This is a bit personal for me, as I have a son whose projected height will be somewhere around 5'0''. I see the way he's treated by others, both explicitly and implicitly, and it's only going to get worse once he hits puberty. He cries about it fairly often, and while we have so far kept him mostly positive and averted "Napoleon Syndrome", he has a good deal of anguish about it, and it's not just "in his head" as the commenter implied.