That was me last night too, I think I was the top player 4-5 times. My friend who joined later on in the game said the second I left my team got dominated.
And snipers can be of benefit! When I'm sniping I'm looking for chances to clear the way for team mates. Like last night I saw a gunner in a MG emplacement holding down about 4-5 guys of my team from progressing forward, I killed him.
Or On Isla of Innocents my team had just played a charge on Obj A. The team counter attacked the squad which did this with about 8 or 9 guys naturally the squad was cleaned out pretty quick. I put a mortar on the objective and sniped 4 guys in a roll keeping the objective safe.
Without my long range support the Obj would of been defussed.
A type I got for when defusing an objective is KEEP MOVING. If you sit still you make an easy target. Move around the Obj holding E this will make anyone attempt to kill you more difficult buying you more time.

