mathprofbrony 
"@BackgrDound Pony #9471":/1141855#comment_4973765
A stretch it maybe, but that really was the nominators' reason. They call it "Marxism isn't Magic." Here, check it out: http://sadpuppies4.org/recommendations-best-dramatic-presentation-short-form/
I was asked to write a blurb about it for a fanzine elsewhere, and my takeway on the common ground that liberals and conservatives could find with the episode was almost certainly that Starlight really crossed the moral line when she stripped the Mane Six' cutie marks without consent. If she had (1) avoided defrauding her followers, openly keeping her cutie mark so as to perform the removal spell, (2) satisfied herself with building a town full of ponies that were having trouble in their lives and came to be equalized and (3) let ponies go with their cutie marks if they decided they didn't like the town, I figure we can all agree that she could have gone about her merry way. (And probably that the town would have shortly collapsed from citizen dissatisfaction, but maybe not; it is a fantasy world after all.)
As you point out, the value of diversity occupies a curious space in the liberal-conservative spectrum. Social research makes it pretty clear that ideologically diverse groups make better decisions, and after all, that's really a key principle behind the smooth functioning of free speech and free markets -- more voices will find and gravitate to a better solution. Conservatives tend to revolt against diversity in the guise of ideas like affirmative action, although achieving diversity is one of its essential goals. Progressives tend to oppose diversity arguments not for the diversity itself but when economies of scale outweigh them heavily, such as when they oppose "school choice" in the name of protecting the public school system.!
A stretch it may
I was asked to write a blurb about it for a fanzine elsewhere, and my takeway on the common ground that liberals and conservatives could find with the episode was almost certainly that Starlight really crossed the moral line when she stripped the Mane Six' cutie marks without consent. If she had (1) avoided defrauding her followers, openly keeping her cutie mark so as to perform the removal spell, (2) satisfied herself with building a town full of ponies that were having trouble in their lives and came to be equalized and (3) let ponies go with their cutie marks if they decided they didn't like the town, I figure we can all agree that she could have gone about her merry way. (And probably that the town would have shortly collapsed from citizen dissatisfaction, but maybe not; it is a fantasy world after all.)
As you point out, the value of diversity occupies a curious space in the liberal-conservative spectrum. Social research makes it pretty clear that ideologically diverse groups make better decisions, and after all, that's really a key principle behind the smooth functioning of free speech and free markets -- more voices will find and gravitate to a better solution. Conservatives tend to revolt against diversity in the guise of ideas like affirmative action, although achieving diversity is one of its essential goals. Progressives tend to oppose diversity arguments not for the diversity itself but when economies of scale outweigh them heavily, such as when they oppose "school choice" in the name of protecting the public school system.