Advocating for vehicular cycling implies that safer cycling infrastructure is not needed because we can just ride beside cars.
That would be in front of and behind cars. 
I believe a person can advocate for both cycling specific infrastructure and vehicular cycling. There is room for both!
Not all bike infrastructure is safe, some can give a sense of security while actually increasing risks. So it is important for those advocating for this to get involved and make sure it's done right.
Since most roads don't have any bike infrastructure, (and most never will) VC is and always will be a handy way to safely ride them.
My favorite take away of all things VC, is the can do attitude. While others say the roads are unsafe for bikes, the VC proponents are out riding them everywhere right now.
Several years back there was a most vocal VC proponent on this board who drove many posters nuts with his rabid VC crusading. I believe he was the reason this sub-forum was created! I also admit he went overboard on his crusade to "save" the non-believers. 
Even so, I always admired his go anywhere on the bike attitude, and his "Every lane is a bike lane!" signature. Yay, for bikes on the road!