When you say "longer hours" do you mean "longer hours than I worked before COVID" or "the same amount of hours, but longer than parents will be working during COVID"?
If you mean the former, then you need a better employer, because agreed, you should not be required or expected to increase your work hours due to COVID, for any reason, and certainly not to pick up the slack caused by parents losing productivity.
If you mean the latter, then this just sounds like entitled whining. Your life has not changed because parents get more flexibility. It's exactly the same as it was before.
Parents don't get to stop taking care of their kids. I know quite a few working parents, and I guarantee you that they don't want to take time away from work for child care right now. But they have no choice. You are incredibly lucky that you aren't a parent right now; take that blessing as your "subsidy" and stop complaining about things that don't actually affect you.