First off, any healer worth their salt is going to throw in at least 1-2 attacks when they've got nothing better to do so it's not like you should *only* be keeping people up. It behooves you to actually throw out the occasional attack, especially as an Operative where you get easy access to excellent damage via Orbital Bombardment.
Secondly, unless your other healer is making up for your lesser healing capabilities, it's entirely possible that a DPS or tank could die when they otherwise wouldn't had you been in PvE gear and, as such, end up reducing raid wide DPS to such an extent that you hit said enrage timer.
Ofcourse I throw in the occasional hit when everybody is topped up and when adds have to be killed, but this doesnt change the game really.
And ofcourse i know PVE geared players have more potential in stats, thats obvious. But I am very skilled in healing and did get through TFB HM dread guard.
I'm just looking to have a ground to work on when people doubt to take me on runs.