There is an absolutely ridiculous amount of pressure on new mothers to "get their bodies back" after giving birth. In fact, a large corner of the diet industry is catered towards women wanting to "lose the baby weight," and it's really bonkers when you think about it. A woman grows a HUMAN inside her, and then gets collectively bullied for not having time to do tons of cardio? That's a big nope.
This shaming of post-partum bodies is just another symptom of our culture's misogyny and deeply engrained policing of women's bodies. This game is rigged so that no women win, even the most privileged and conventionally attractive women are privy to this criticism and internalized shame.