As a fat person working very hard to get healthy, I agree with the OP. SEEMINGLY, healthy (read looks like they are thin) people do work hard to lose that 5 lbs (or whatever % of fat), using very low calorie diets (VLCD), does seem a bit overboard to me.
I am on a VLCD, and when I am not, I eat strict Paleo. Doing this I have lost 106 lbs in the last 6 months, reduced my high blood pressure and the amount of LDL's that were clogging my arteries. I have also gained a understanding of food, through research. There is also an emotional component that comes along with being fat. Except for a few misguided "disability" recipients, no one WANTS to be fat.
Food has it's place, it is there to keep us functioning and alive. What I have learned is that food is not a friend. Food doesn't bring comfort. Food is what it is, food. I treat food like what it is, my addiction. The down side of that is that I can't just stop eating (I've tried that, it doesn't work).
I am closing in on my goal weight of 185, which is still going to be "fat" to some, and too "thin" to others. At that weight, I can walk into a CrossFit gym, and just be an out of shape person, not a fatty who can't control herself.
I understand the reasoning around being angry at fat people. I do it too. Walking into the grocery and seeing some 400 lb woman riding around in a scooter shopping cart with her "healthy" whole wheat bread, her WW frozen dinners, bottles of Diet Coke, and a bunch of 100 calorie Snack Packs. I just want to shake her (or even him) and scream at them! But, we must all choose. It took me 44 years to realize that I am killing myself and digging my grave with a fork.