This isn't anything new, since most DS games with traditional controls don't accomodate left-handed people anyway.

Not true at all.  There isn't one DS game that I have played that does not force you to use your right hand to operate the stylis.  With the 3DS you are going to be forced to write right handed if you want to use the analog stick.

If you read any book (including any religious text) or watch any movie evil usually outnumbers the good in terms of sheer numbers but the good usually find a way to triumph.

So going by that logic you righties are the spawn of satan and we lefties are the good ones! 

Did you miss the bolded part?

What does Prime Hunters make you do?  I don't own a ds but I plan on getting a 3ds and I'm left handed.

I think you are missing my point. Most games are not a problem. But some game controls have you use the stylis and the D-pad at the same time.  This is not a problem on the DS since you can use the XYAB button instead of the d-pad.  But now the 3DS has an analog stick on the left side and there is no way to mimic this operation for left handed people.  Again, traditional controls are not the problem.

You could just hold it upside down, and then use a mirror to make the image the right way round... though I am not sure that will quite work

Normal right handed controls have the left hand operating the d-pad to move the player and the right hand you use the stylis to look around and aim.  Being left handed you use the XYAB buttons to move. This is the same control for all FPS on the DS. Moon, Call of Duty, Metroid Prime Hunters, to name a few.

...I don't get it.

What does being a liberal have to do with your abilities to hold a handheld gaming device?

Because Obama is left handed