I guess it’s bait for people who like to judge. The idea could be: it’s not responsible to quit science for this and being a mother makes irresponsible choices even worse. That’s not my point of view, but I know people whose life seems to be so empty that they feel a constant need to look down on others and the “mother” information gives them at least 5 more minutes of talking shit about how this is a terrible decision.
I see it the other way around. Older people eat up clickbait news, and older people tend to be parents, so identifying the woman as a mother makes them go “she’s someone like me” while identifying her as a scientist is less likely to resonate. It helps some people imagine themselves in her shoes.