The bathroom by the Japan QS in Epcot does not have a changing table. Many at DTD don't either, and the bathroom in China didn't until they renovated it. Several times have I squatted on the floor in that tiny Japan bathroom changing a diaper.
I am one of those weird moms, I suppose, that always changes a diaper in a bathroom, or at my changing table in my home. And yes, apparently it is weird because in a lot of mom forums, a home changing table pops up as one of the most useless baby items. "You will end up just laying down a towel on the floor or the bed or wherever." Not me, I always change on the table with my wipes and diapers and cream and all that junk right there. Out in public I believe urine and feces belong in a bathroom. I have my own changing pad and have laid my kid on the pad on the floor many times. And although DH will, I will not change a diaper in the car either!
I do think the employees should have kept their disgust to themselves and wiped everything down once the family left. It sucks, but that is how retail works. I once had a grown woman pee in a fitting room when I was selling wedding gowns and I just had to grit my teeth and call the carpet cleaners.