This is a really straightforward situation that doesn't need to involve derogatory labels. The space that you purchased is up to halfway up the middle of the armrest in the down position. If you cannot contain yourself to that space for whatever reason, you can: buy a second seat, buy a seat in the front cabin, take a train, drive yourself to your destination, or charter an Antonov An-124 to get you there. In no way is any airline or any fellow passenger obligated to suffer for your: personal decisions, lifestyle, diet, or medical condition.

FWIW, I am 6'3" and 265 pounds. I go out of my way to not impose my gargantuan proportions upon anyone else. That includes using the seat in front of me to wrench myself out of and into my seat. All you need is strong abs!