Which gets into an entirely separate (though related) issue, where workers with children get benefits and accommodations that childless workers don't.
Sometimes it's overt and blatant like in your case, others, it's more limited to interactions and relationships.
A few jobs ago, I worked in a small office where the owner was good about approving PTO, but didn't want more than one person in any given dept out at the same time (ridiculous, but that's how he was).
I planned a vacation of a long weekend one summer and got my PTO approved in like February for this long weekend in June.
Literally 3 weeks before, this lady I worked with tells me that I "need to reschedule my PTO".
After looking into it, I learn that what's really going on is that she wanted to take a week long vacation with her kids since they'd be off for the summer, and one of my days overlapped with the week she wanted to take.
I refused, saying that my friends and I had already made arrangements.
And then she blew it up, in the office in front of everyone, and told me how I was being so rude and mean and inconsiderate, that I could go and do things whenever I liked because I didn't have kids...and that I "just didn't get it" and could never possibly understand how hard her life was because I didn't have kids.
I assumed that my boss and other coworkers would see how ridiculous she was, but while they mostly kept quiet, the ones who did speak up actually did think I was being unreasonable for not canceling my vacation to trade with her, seeing my plans as less than hers, just because she had kids.
I learned to get comfortable with coworkers thinking I was an asshole, though, and enjoyed every moment of that getaway.