It's kinda weird that some people are SO into being in everybody else's business that they can't even read a space joke without having a stroke. Like, damn...did a fat guy steal your girlfriend once? Calm down.
I think it's more they heard the weight thing over and over and over and people are holding it as a fact and it's annoying when something is held as a fact cause it's interesting even though it's wrong
Nope, this is a joke. "You're on the wrong planet" should clue you in. This is a common joke, and recognized as one. It makes no claim to being fact, and anybody who feels like they have to fact check an obvious joke--again, "you're on the wrong planet," absolutely no way this can be construed as trying to be serious--has some kind of chip on their shoulder.
Dude. The entire social function of a joke is to signal group membership (who laughs? Who's not allowed to laugh? Is there a butt of this joke, and who is it?). Jokes are social power plays. The entire point of this joke is "fat people are worthy of shame."
http://www.exploratorium.edu/ronh/weight/
And is that supposed to be Mars?..why is there a McDonalds? Haha