E.g like this Rémi Denis-Courmont guy, a VLC contributor working for Nokia, killed the iOS VLC port for violating some GPL technicalities, despite the code being available, the users wanting it, and the team porting it to iOS for free.Hang on a minute. What you're trying to push aside as a technicality has been a recurring sore point between Apple's App Store and the FOSS community, and Denis-Courmont is far from the only person who has been upset by attempts to distribute GPL'd software via the App Store under terms are incompatible with both the letter and the spirit of the GPL. [1]
But in this case, since we're talking about an MIT licence, it's hard to see how the CLA makes any sense. What can it possibly allow anyone to do to anyone or with anything that they couldn't already do anyway under the MIT licence? They could release the code under a licence that doesn't even require the credit/copyright/disclaimer, I suppose, but those aren't exactly a heavy burden. Other that that, the whole point of licences like the MIT ones is basically to avoid having the kinds of restrictions that would ever result in copyright enforcement action, so it's not like you need a single party with standing to sue or issue takedown notices, for example. I don't see what anyone gains by having this extra hoop for contributors to jump though.
[Edit: Someone posted the actual text of the CLA. It seems to address significantly more that just transferring rights to the jQuery Foundation, so there may or may not be sneaky legal shenanigans going on here that I wasn't considering above.]
[1] http://www.fsf.org/blogs/licensing/more-about-the-app-store-...