To get more money, simple as that.

We are the mineshaft canaries. Clearly not a market worth pursuing on our own but we can smell nasty stuff before the real gamers have to be subjected to it. Meanwhile, if it smells good, then it's time to send it on to actual customers.

It makes sense though, as a game company if you saw the opportunity to do an easy port and gain more sales why wouldn't you.

It worked out for them with Chinatown wars, they sold an extra 960k copies with the PSP version, I'm sure it was fairly easily ported too.

They took our games! please, its been happening all gen, not just on Ninty systems. Oh and add TWENY and FF thearythm to that list since they went on iOS. As others have said i dont see the big idea unless the original version was severally gimped. they either want more money or the original didnt sell what they originally intended, and LOL at saying the original sell better than late ports, some might fine logic right there.

I hope a main line RE game on 140 million systems sold better than a HH RE that had what 15 mil systems when it launched. Question tho what do you think RE: rev numbers would be if 3DS install base was = ps3/360 not combined? Either way I'm glad I have it for 3ds it was a great game, now think of all the new people that get to expeirence it. Maybe it will make RE7 a better game ;). 

To clarify my earlier post, full of allegorical bitterness as it was, i wouldn't have an issue with it but for the fact that it seems like games only flow in one direction: Nintendo -> Microsoft/Sony and never from either Microsoft/Sony -> Nintendo, with very rare exceptions like Modern Warfare, Ninja Gaiden 3, Mass Effect 3 (gimped) and Arkham City (appropriately enhanced for a year-late release).

If it seemed like the flow was more equitable, i would have less of a problem with it

It's likely that third parties that create exclusives are owned by the first parties or bound by contracts. It seems to me like Nintendo is not a fan of either of these.

Really? I thought it was fresh and much more arcade-ish/oldschool, and it pushed the DS technically too!

Really?  because the OP only mentioned three instances of Nintendo third party exclusives going to MS/Sony while you've already listed 4 that go the other direction.  

It's not like the other consoles have some tons of third party exclusives. That's just not the way the industry works anymore.