Flare and fly - I tend to hold your position that some of these guys get settled in, no body cares how fat or sick they are, and these guys will do anything to keep their jobs.
My own experience has seen the following -
A guy that flew across the country for his medical, to go to one specific doctor...this is a guy that couldn't fly in a cabin above 6ft and resulting in him flying at stupid low levels, burning way to much fuel, and flying on fumes many times.
A guy that never got a first class med because 'sending the EKG data to the FAA many times are a mistake'..so you have an overweight 65 year old guy, with high blood pressure, running on a 2nd class, probably taking something prior to the medical to game his medical into the proper territory.
This is all about holding standards. You either care about the passengers, safety, and professionalism, or you don't, where it's just a paycheck, a title, an easy job, or whatever.
Whatever the case, 300 lb pilots shouldn't be flying planes.