I think they wanted something closer to modern times, to make it more relateable, rather than the distant future feel of the other Trek series, to fit with the intro montage of exploration through the ages from the past to the future.
I'm not saying it was completely successful, although I got used to it, and even didn't mind it. It wasn't very Trekky though, and not even an original song, so I get why people hate it. They were originally going to use the music that ended up over the end credits, which would have been better.