You make valid points for other players to consider, and I have felt your frustration many times; however, I disagree on the statement concerning whose "job" it is to watch doors/turrets.
As a team player, it is everyone's task to cap, guard, pass, etc. It takes two seconds to throw a CC, which could result in a win for my team.
As a PvP healer, there is no denying how difficult it is to keep, not one player alive, but my entire team alive, cleansed, obtain objectives, and dance around enemy players because they see the "Yellow Star- Everyone Kill Kissimee!!" above my head. But quite honestly, these challenges are what lure and motivate me in PvP.
Should dps cap/guard/carry? Absolutely. But keep in mind, they have predicaments too. Killing enemy healers, crowd controlling, and capping doors, while desperately keeping five players from obliterating their healer, is no easy feat.
In order to obtain victory, it ultimately requires all players becoming conscientious of their surroundings and sensitive to the needs of team players.