Because people (society) is always on the look out for proof that women are inferior, so when one woman does anything less than perfectly, it naturally shows that women everywhere will fail similarly.
Men are treated as individuals and can fail, succeed, have the occasional slip up without anyone questioning whether men are competent enough to be in the workplace. Even when the slip ups are things like I mentioned earlier - crashing banks, fiddling libor, etc. When Barings happened, did anyone look at Nick Leeson and say, well this shows that men shouldn't really be in banking, he's let them all down, this reflects very badly on all men in the industry. No, they didn't. One woman "referenced" her family duing a speech and multiple posters are saying yes this is bad, very very bad indeed. Op claims that it negatively impacts all women working at that company.
I thougth attitudes like this were on the way out, it's really sad to see women supporting this view.
Incidentally, with the crash a few years back, and the global recession that banrupted whole countries, there was a suggestion that maybe more women bring "balance" due to being more risk averse (pretty big generalistion, I think they look for risk takers and so that's probably what they get from both sexes!) but anyway - it has been alluded to, that maybe women have something of value to bring to the table in the financial sector at least.
Also FYI I work for a big global company in financial sector and our men and women at leadership level all do this "look at me I'm a person here are my kids" stuff. It is very popular at the moment. Maybe this woman came from a different sector where it's the norm, maybe she's ahead of the curve, maybe she just did her own thing.
Really can't see how she has personally tolled the death knell for all women at the company by "referencing" her kids in a specch I mean come off it.