I'm a little confused by this argument, because (if you don't have children) the time you had to exercise pre-COVID is still available to you. If you used to get up at 7am, go out for a run for an hour, come back, shower, and start your work day, you... can still do that.
If somehow you are unable to continue this routine during COVID, perhaps because your employer is expecting you (as someone who is childless) to work until 11pm, which makes you too tired to get up to exercise, then shouldn't your ire be directed at your employer for imposing unreasonable work expectations? It seems pretty pointless to get pissed off at parents because of that.
I also do not have kids. I put in 8-10 hours a day, just as I did pre-COVID, and have the same amount of free time as I used to. It's very different free time, and there are mental health implications to that, but none of that in any way has anything to do with my employer showing empathy toward parents and making allowances for them to take care of their kids during the work day.
The big difference between parents and non-parents is that child care is not optional during work hours. If your school or pre-school or day care or whatever has shut down because of COVID, you can't simply opt out of caring for your child because you have to work. COVID has not given non-parents any new non-work responsibilities during work hours. But it has certainly done so for parents.
When do parents get this self care? Between work, kids, sleep, what free moments are you imagining?
If you can't fit in a workout when you're now without a commute, then I'm confused. And, if you equate a workout with the relentless task of educating and entertaining a toddler, well, you must be _very_ serious about your gym time. Little kids are 7a to 9p, _maybe_ a nap on a good day of an hour, and oh, if you slack too long they just don't get to learn math.
Stop working late. Take care of yourself. Stop blaming people with other responsibilities if you're not doing that. Above all, develop empathy - this is hard for everyone, so stop playing the "those people are getting benefits I'm not" game.
But from what you’re saying, it sounds like you need better communication with your management. Otherwise, I can’t imagine it having been a healthy environment pre-COVID.
1. Yes, children need self-care. But so do adults. Just as it is wrong to tell someone they can't take care of their child, I'd say it's equally wrong to tell an adult that they can't, for example, get their exercise time, because I would consider that also a human necessity. You risk early death if you do not exercise. For medical reasons I don't need to state here, the risk may be even higher for me personally if I don't get that time. Other adults have other medical conditions they need to attend to. However, not all workplaces recognize these as on par with taking care of children.
2. Those that choose not to have children may also be playing essential roles in our society in their off-hours. Heck, they may be volunteering at the Red Cross and saving other children from death, who knows, that may be why they chose not to have kids. Should we judge?
3. Let's not underestimate how important mental health is to society. People will die (from various causes, including suicide) if they are made to work late every day. Yes, I agree that children need to be taken care of. But the response to that shouldn't be to take an unreasonable work share given to a working parent and shove the excess onto the single/child-less workers in the same organization to slave away for 80 hours a week. This actually happens, and I have seen it happen. Instead, the response should be to give everyone a fair, normal 40-hour work share and let them do whatever they need or want to with their spare time.