Before I go on my (hopefully short) rant I'd just like to say that I'm baffled at how so many Coldplay fans can disagree on so many things when it comes to our taste in music. I guess it's to be expected though.
1) I think most the people who don't like PoC are the same ones who either A) haven't ventured out into other genres of music or B) just don't like other styles.
I'm inclined to believe that most haven't even given other types of music a chance. To those who have, that's fine, not everyone likes everything. Some like vanilla, others like chocolate, and some enjoy both :D
2) Before I became a CP fan I listened to a lot of rap (Tupac, Bone Thugz, etc), Rock, Pop, Country, whatever have you. I've been musically rounded so to me the new style is a "Coldplay-ized" version of different genres, which at first I didn't like, but now I *LOVE.*
3) Chris Martin recently said that Kanye West had redefined the way we interact with music in the sense that (my interpretation here) before we had metalheads here, hip hop fans there, and people were in their own musical box. It's this last decade that we've mashed up different styles (Jay-Z + Linkin Park, etc) and produced something completely different. I'd embrace it, I think it's great. I'd hate it if CP was 5 albums in and sounding the same. Give us a few songs that are oldplay, but give us something fresh too. That's how bands get boring, they just redo what they've always done. CP is better than that. They venture out, they dare to incorporate new styles and develop.
4) Rihanna's voice is beaut, and the song is a toe tapper. It is also a grower - you need to give it a few listens for it to hit you. When I first heard Every Tear I hated it, but now I love it. It's brilliant. Here's the problem: Most people who call these tracks terrible are comparing it to an unrealistic expectation: For Coldplay to dish out the same types of songs. If you're comparing it to Parachutes and A Rush of Blood then yes, these songs are completely off from those sounds. But if you judge it for what it is, I think there's no denying they did a great job, even if you don't like the new genre/style they're adopting.