This brings me back to the point I was trying to make about different cultures. To you, having a child go to the bathroom on the side of the street is disgusting and completely inappropriate. To the Chinese, it is perfectly acceptable.
Similarly, to you it seems fine to have a child use a portable potty, in a very shielded and discreet manner, while standing in line at WDW rather than get out of line to go to the bathroom. To the VAST majority of Americans, that is going to be considered disgusting and completely inappropriate.
You simply have a different view of it, and my guess is that it has more to do with a different culture than anything else.
I'm willing to bet most people from Boston would think that it is horrible to pee on a tree in your own backyard. I'm also willing to bet most people rural Texas think it is a waste of time and water to go inside and use the toilet when there is a perfectly suitable tree right there next to them.
The thing is, when the Texan goes to Boston, he should probably try to adhere to local views on the matter and let mother nature water the trees when it rains rather than taking on that job for himself.