People take care of the uplinks just fine, provided they can get there. Focus fire on the AT-ATs is what seems to be the main issue. They rarely get down to half health, if that, which is probably teaching people that it's futile, so they go back to shooting/dodging storm troopers, which makes winning even more hopeless and so on.
I see this in Dirty Bomb too. People prefer to run around and chase the enemy, rather than damaging the objective that's trundling down the road at glacial speeds. Everybody waits for the big hitters to do the heavy lifting, even when the objective has only a sliver of health left.