While I absolutely agree that there is a ton of bad behavior in the world from people ignorantly pontificating on things outside their wheelhouse, it is incredibly arrogant and ignorant to suggest that non-parents know
nothing about parenting. It just doesn't even make logical sense.
If you are constantly late for everything and always blame it on your kid, you are doing something wrong. You should know by now that things always take longer than expected with a kid, and plan accordingly. No, you will not always get it right, and that's fine. Occasional lapses are expected and accepted. But if it becomes a regular pattern, you are simply shifting blame for your poor time-management skills onto a child that does not deserve that finger pointed at them.
If you are going to discount my opinion out of hand, I suppose I can't keep you from doing that. But, my opinion happens to agree with that of a parent upthread, so... take that as you will, I suppose.