As much as they deny, it definitely IS jealousy. Of youth, of an amazing figure, of looking good.
I remember there was a thread a while back. OP was young and looked like a blooming supermodel. She really did. Not in that fake MN way, where a middle-aged woman size 16 is told how 'amazing' she looks and what a 'tiny waist' she has. No, the woman in question was young, tall, size 8, hourglass, legs for days, gorgeous. And she was wearing a red bodycon dress, midi length, just slightly booby, but not all-out. For a special occasion. She looked fantastic.
You won't believe the comments she got. Tacky, cheap, dated, desperate, try-hard, crying-laughing emojis, suggestions for Phase8, Hobbs and Toast-tents, the lot. She looked like Margot Robbie in The Wolf of Wall Street, just dark-haired. It WAS jealousy, 100%.
Incidentally, I'm myself very tall, size 6/8 an hourglass, an ex-model (back in the day). Want to know the single group of people who called me 'skin and bones', 'told me to eat a burger', etc? Hint: it's not slim women, it's not young women (whatever their figure), it's not any kind of figure men.