Thing is, I've never shown any hostility and I don't see how agreeing with "it's not my problem though" suggests I do. However someone ranting starting with "fuck off" makes me think they suck as a parent.
I show my empathy by putting up with kids everywhere I go. Parents can show their empathy by literally just not ignoring bad behavior. Which in other comments I clarified is the only thing I actually have issues with. The entire store should not be filled with shrill screams while the parent flat out ignores it for 10 minutes. Not too much to ask.