Having defensive town makes sense to me for two reasons.
One, scum have a lot of incentive to kill one another. It's the reason why WyIted is going so hard on the "figure out the other scum team" train at this point - he'd prefer to get rid of the other scum team while giving his more opportunities to act.
Two, the factional bulletproof is inherently less protective for town. There are six targets for town, any one of whom is more likely to have been shot during the NP than the opposing scum team, removing that bulletproof. That puts more town members at greater risk for future NPs. It strikes me that without an obvious Doc in the game or some other protective role that goes beyond an even or odd night angle, that puts town at a serious disadvantage.