how serious should we be?

After a recent string of posts on a forum thread I have to ask myself how serious should an rpg game world be taken?

Since the thread was about Gamma World ill use that as my first example. First of all GW can be run as a very campy humorous game, since you have monsters as whacked as the Yexil who feed on fabric and really love an all synthetic outfit like a 70s leisure suit. Keep in mind that physically the critter looks like a sphinx in a lot of ways. So we have a creature whose composed of bat wings on a lion body with a human head, who can be bribed with a leisure suit right out of Saturday Night Fever. But is that any more ridiculous than a peryton, a creature of actual mythology that has a deer's head with antlers, on a bird body, that casts the shadow of a human being and eats just hearts? With GW you can at least use the excuse of genetic engineering or nanites from before the Fall.

But it still begs the question that when you get down to it, how can you really take any non real world element in any game of any genre seriously? Isn't the Force just as ridiculous as a flumph or a screamer? What makes a +5 sword of blending any more believable than a laser rifle or a lazy hyena headed humanoid?

If we even just accept things like other sentient races and magic, how many times do real world elements like slavery and discrimination rear their head in a game? Human beings have slaughtered untold millions because of differences in belief and skin color, and somehow we are supposed to believe that they open their arms to genuinely alien looking and acting races like dwarves and elves. I find it far more believable that the mutated humanoid badger was to beat the crap out of the party, take their stuff and sell them into slavery far far more than I can believe that halflings are a peaceful, pastoral and free people that just kinda while their lives away farming. The only real record of different cultures interact that we have to work with paints a much grimmer story of war, subjugation or extinction.

But do we really want that in our games?