Taking personal responsibility is so old fashioned.
It is much more fun to blame somebody else for your problems!
They arent blaming you for them being fat.
They are blaming you for their perception that you are not accomodating them.
The easy answer is that: nothing is built for general public use today for body styles 2 or 3 (or more) standard deviations from what is defined as a normal healthy weight/body style. Unless it is specifically sized for it, like clothes. And then you pay more for it to be that way.