Not always. Not all the time. Like I said, you have to look at the facilities and see what is available. If you are alone, with a sleeping newborn baby in a pram, and the ladies toilet is not practical to use without waking the baby up, and pooing with it sat on your knee, then is it really so entitled to use the disabled loo?
If you can, use the ladies of course.
I have never ever seen anyone take a newborn baby out of a pram, leave the pram outside the door, and go to the toilet with the baby sat on their knee. Never.
If you can get a pram in the ladies then great, but you cant always.
If I was out and about, and chatting to you, and said crikey I need the loo but look its upstairs and I cant get a pram in, would you really tell me to take the baby out, and carry it upstairs? Really?
I cant see why these facilities cannot be shared nicely by those with a genuine need.