I will guess the sentiment is common to people who get upset when their coworkers get to take cigarette breaks and they don’t. The perceived unfairness of them getting a benefit you want (10 minute break every hour hanging out behind the store) compounded by the feeling that they are the better one because smoking is a bad thing anyway so why am I being “punished” for making the right choice?

Those of us with parents understand the other commenters point about what’s next “getting upset about cancer patients going to the doctor” because yeah...we love our children very much. Childless people can be forgiven for thinking that the time is more akin to sitting around the table playing a board game with everyone laughing and having a great time so they are resentful that you are getting a benefit in the form of extra time off and for a lot of them probably compounded by the feeling that they made the better noble decision by having no kids.

In both cases the business is letting it happen (smoke breaks and child care) for really only one reason. It makes more business sense to accommodate the issue then it does to try and fight it when the cause is societal and pervasive.