Honestly, I don't see why other people should care. If someone doesn't like the idea of a unisex/family/companion restroom, they don't have to go in it. Plus, the presence of one means it's less likely for someone of the opposite gender to be in the single-sex bathroom.
I don't think it's that people don't like the idea of a family/unisex/companion bathroom. I think it's the fact that this topic is like beating a dead horse, and I don't think that the two sides will ever see eye to eye. There will always be parents who feel that it is their "right" to take their entire family into the C.A.R. since it's the only "Family bathroom" type facility in the park and it doesn't matter what they're doing in there (toileting, diaper changes, costume/clothing changes, fearing allowing their 10 year old to go alone, etc).
There will also always be the people who say you should *NEVER* use a C.A.R. unless you are a person with a disability who has a genuine need for that facility because there are so few of them available.
And then there's the 3rd group who says be considerate. If there's nobody waiting and it's just a quick in-and-out #1 trip, go for it. Anything longer and find a standard restroom.
The fact is that there are a limited number of companion restrooms that used to ONLY be marked on the WDW map for guests with disabilities (they were not marked on the regular park maps) and the Disney website makes it fairly clear that these were not intended for parents who fear allowing their child into the restroom unaccompanied.
"Restrooms are available throughout the Walt Disney World Resort.
Companion assisted restroom facilities are available in addition to facilities designed for access by Guests with mobility disabilities."
When looking at a list of C.A.R.'s you will see that there are 6 in the MK, 7 in Epcot, 5 in DHS, and 5 at AK. Compare that to the literal HUNDREDS of standard stalls available in the regular bathrooms.
A bit of common sense and decency goes a long way