Well, from the article one of the big cons to disk brakes is the safety issue related to having a hot, spinning knife-like rotor. The proximity of the riders to each other and how crashes happen in road racing (pile up crashes that seem to always happen at the beginning of the TdF, for instance) makes it a much different situation than mountain or cross races.
I'm kinda surprised at how many riders don't want them in the peloton. I figured they would be all about them.