I think the OP is kinda getting saddled with a whole lot of built-up resentment. The "fuck you pig scalper" argument might have a little more weight behind it if the OP was flipping something that was literally needed by others, but a 3DS? One that is arguably no different from a regular, run-of-the-mill 3DS one can find with ease? Flipping something like that for a profit isn't "fucking someone over", it's being smart.
I'm a university student. I'm short on cash. Would I have bought one of those anniversary PS4s a while back and sold it for way, way more than it was worth, had I been more attentive? Damn straight I would. Some people obviously thought it was still worth the money, and I like being able to pay for food, school, and housing. Would I do the same if the object in question was a necessity? Probably not, but these items aren't. Nobody is being fucked over, they're getting upset over consumer luxuries.
Don't get so riled up about the small stuff, folks. Go buy a plain 3DS if you want one, odds are it'll do the exact same thing.