Personally I think dadbods are a symptom of a deeply unhealthy society. We certainly shouldn’t associate fatherhood with over eating and under moving. True body-positivity is promoting healthy bodies.
You're not wrong, though I find it a bit weird how at least for the moment only cis women get to enjoy plus-sized models appearing in clothing advertisements.
Then on the flip side you have plus sized celebrities that get hate for losing weight like Adele and Rebel Wilson. Although along that vein it seems it's pretty equal as Jonah Hill and Ethan Suplee got similar criticisms when they lost weight.