Game Informer seem like a right horrible bunch. I read that RPS article last night and while it was a light hearted dig at the idea exclusivity and gameinformers rather antiquated concept of information control it was very much giving the credit to them and directing readers to their site. Their reaction is just childish, nasty and indicitive of how out of touch they are.
What's more it shows how much stock they put in being the only people with the access which, imo, makes anything they write utterly untrustworthy. If they are prostituing themselves for exclusive rights what is the price? It certainly isn't objectivity. Kinda makes all this "blow your mind" stuff rather suspect if they're just an extension of the PR team.
I don't want to turn this into an argument about Game Informer, but I will say this: they're a business. Like all businesses, they have to protect their assets. Regardless of what the context of that RPS article was, the fact is they had cropped Game Informer's watermark out of their screenshots and posted them to the RPS site, infringing on Game Informer's property. As a business, there can be no exceptions when it comes to protecting your assets. You let one thing slide without proper rights management, then others will argue that they should be given the same privilege - and you won't be able to hold up in a court because you didn't defend the initial infringement.
It doesn't make them nasty, it makes them a business. Is it harsh? Yeah, sometimes. But it's necessary if they want to continue to offer exclusive content to their readers. You may not care about that (most people don't), but they certainly do - and they're well within their rights to protect what's theirs.
If it makes you question their credibility as a press outlet, that's certainly a fair conclusion to come to, and I won't challenge you there - but keep in mind that, regardless of whether or not they're considered "fair", they're still offering content no other outlet is. And that'll keep people subscribing.