If we are going to reject any camping appliance on the basis of misuse by someone, somewhere... there wouldn't be much left!
In my opinion, for those who make regular use of the onboard toilet as their primary facility, and especially with more than 1 or 2 users, a conventional toilet and black tank is the better option. It allows greater capacity without the difficulties of carrying and emptying a larger, heavier portable waste tank. For occasional light
use, a porta-potty or cassette makes sense.
I agree that when possible, it is better to empty a portable waste tank at a dump station rather than a bathroom with flush toilets. They really aren't meant to receive a lot at once, and that's how messes happen.