My pet theory is that the ULTIMATE PURPOSE of the game is not the propagation of universes, but facilitating the emotional growth of a bunch of teenagers. The trolls didn't quite manage to learn the True Meaning of Friendship, so Skaia tosses another unkillable endboss at them.
Except trolls don't really make friends so much, being the violent recluses they are. The closest we've seen to actual friends under normal circumstances are Viska with Equius, and some of the ancestors too. The ancestors were mostly together because of fighting other people, and Vriska and Equius were both trying to backstab each other.
Is SBURB on the other hand is designed to have the players conform to OUR idea of friendship and acceptance and all that, then it's design is inherently racist to the extreme. Also, if that's the point of the game, how could the squiddle session fail? And why did scratching for the trolls create a MORE violent universe? Surely if that game is won by love and acceptance, why have both instances we've seen of a scratch caused the players to grow up in a more hostile and dangerous environment?