Gosh, yes, public toilets in China were appalling! And in restaurants too, I went to the toilet after eating when near The Summer Palace which was a big mistake. Apart from being filthy, it was right next to the kitchen, had no door and no sink and there was a sack of onions stored in it!
In Tienaman Square, I joined the long queue of mainly Chinese people and after a while the elderly attendant grabbed my arm and pushed me into the disabled cubicle. I tried to resist but then realised she was showing me that it had a western style toilet rather than a hole in the floor. After that I always used the disabled toilet if there was one - as did the rest of the ladies on the coach!