I'm not sure any comment about weight and health represents a 'search for perfection'.
We all know that excess weight has been proven to not be good for us. It's connected with a lot of health problems such as knee injuries, heart problems, even some cancers. We all realize that. An effort to slim down a few excess pounds is always great. Maybe by some twist some wording in that earlier statement could offend someone, but the idea that it's good to lose excess weight should not.
For many people, they have issues of mobility or health problems that make losing weight tough. For some it's a sedentary job, a long commute, and a 'burn out job' that means when they come home at night, they park in front of the TV and spend a few hours in total shock, too burned out to exercise, until they go to bed. I know a lot of people like that. They come home and basically sit there and try to mentally recover to go face it all again the next day! For others they're battling heredity, eating habits (also 'inherited'!) Some are fighting poverty - yes, cheap food is often fatty and starchy. Eating well takes both money and effort.
For a lot of people, riding can be just one more part of a new healthy lifestyle. As long as the person is appropriately mounted, I see no problem with that.
If someone is so heavy they can't get on a horse, and I've seen people like that, they might consider driving - again with a horse appropriate to that vehicle-driver weight.
Driving, done properly, is a nice little workout too. But so is briskly grooming, cleaning hooves, carrying bales of hay and buckets of water.
The main thing is to have something that gets a person out there, moving around, burning off excess pounds and having a great time.