I question the verbiage "to cave in" and its negative connotation, not because I'm an Apple fanboy (though I am), but because it makes it sound like Apple really didn't want to approve it but was forced under pressure to do so, against all their wills. Which I just think is not accurate.
First of all, Trent's great, but his outrage is not going to pressure Apple to do jack shit. Think of some of the choices Apple has made in the past and the huge commotions they have created on and off the web, many that were much, much bigger than Trent's little ranting. Did Apple "cave in" to the pressure every single time? Nope.
Second of all, could Apple really not have wanted to approve the app? I mean, come on, pretty much any app is good news for the app store (unless it's a trojan/virus), and such a high-profile app like the NIN app? Of course Apple wanted to approve it. But for some convoluted reason, it was not, and now they've fixed it.
So, I think the much more accurate way of phrasing this is that "Apple came to their senses" rather than "Apple caved in". And yes, I do think there is a substantive difference between those two.