I weigh about 120kg (18 or so boulders). I am fat. I know this, and I intend to attempt to lose some of that weight, and make changes to better my health and quality of life. I don't need some 5'4" 200 kilo hamplanet who can't take responsibility for their eating habits telling me that losing weight is 'fatphobic'. Also you are absolutely allowed to make fun of me for being fat.
Being fat is unhealthy 99 times out of 100, and while it may be easier for some to lose weight than others due to circumstances or genetics, losing weight for the sake of improving your health is a worthy ideal, and people who say otherwise have decided that instead of improving themselves, they'd rather everyone was just as miserable as them.