1. My problems with drow aside, which I'll address below, they do make scary villains. They're smarter and live much longer so can play the long game, having plans that span decades or centuries. I play D&D and tend to set my campaigns in the Forgotten Realms (some dislike the NPCs, but I like having easily referenced maps and organizations like the Harpers or the Red Wizards so I don't have to make more things up than what I'm throwing at the group), and the FR's history is full of bad decisions and overreach by the elves (consorting with demons for power, developing magic that's too strong for mortals to handle). Not to mention the racist/xenophobic angle. Also, they're depicted as being very pretty. And for some that has great value (why the "evil" races always seem to be hideous). Why I like DMing, can change those things and not have default "evil" races (not much of a fan of alignment as it is), just groups with sometimes competing goals.
Not from those on the left, it was a foot in the door to full citizenship. Keeping them as cheap labor to save money and undermine the bargaining power of working class citizens perpetually is a right-wing thing. Like I said, worked too well.
People (usually men) want to see things they want to f##k. Female goblins/orcs/dwarves are probably not going to do the trick, so they're not included.
I have several problems with the drow. 1. Hard explaining to friends who aren't white that most of the subraces in your fantasy setting that are black-skinned are inherently, irredeemably evil (drow, duergar for example). 2. Hate that subterranean races are black-skinned in the first place, should be pale white. A lesser complaint, but come on fantasy writers.