Is it just me, or was the religious subtext (or, really, hypertext...) of I Am Legend enough to make a good Omega Man/zombie flick into an entirely disappointing venture?

I mean wow. The first... hour or so? Awesome stuff. Great chemistry between Smith and the dog. Beautiful scenery. Mannequins. Shit, the movie was rolling.

Then they had to try and give the film a message. Why couldn't it just be? Hm? Seriously. Why couldn't the movie just have been itself? But no. They had to turn it into something bigger. Rawr.

Don't get me wrong. I enjoyed the movie. But the entire last part of the film left a bad taste in my mouth.

I'll do my best not to spoil anything specific, suffice it to say the movie's representation of Satan is the only religious element that didn't rub me the wrong way.
Though, the entire time part of me was drawing parallels to Halo's Infection game-type...
Is that bad?