I don't think you're overreacting.

I think it's perfectly ok to use a disabled toilet if you have pram/trolley/kids. In fact, I can't recall ever seeing a disabled toilet in use by an actual disabled person. EVER!

Parent's rooms are for parents with kids. I will accept a disabled person using them. Anyone else can go to the normal toilets. A hundred meters is a long way when you have to go so I'm not surprised people are too lazy to go to the normal toilets.

My DH is a cleaner. He tells me the ladies is always more filthy then the men. It doesn't surprise me in the least from my experiences of female public toilets.

I was feeding DD in a parents room when two ladies came out of the toilet in there. Together. No idea what they were doing.

ETA Talking about poor planning - Where DH works, they have done renovations recently (as in within the last 12 months). They put the baby change in the female toilets. He was peeved because it basically means he can't change DD if he decided to take her there without me.