The thing about breaking ladders is you have to swing a weapon to do it and the thing about swinging weapons is that it makes it so you can't possibly be shielding while you do it so as long as your team has archers or throwers, you can just harrass or kill the ladder breakers while melee guys charge up the ladder. It's not rocket science.
The guys on the roof still have the advantage of better cover and range on their weapons in this situation but the thing is, you can't win a round from a roof unless you just kill everyone on the enemy team. Eventually it's going to go to master of the field and the flags are never placed on a roof with no map ladders to it.
I'm all for kicking people who can't do anything from the roof they are on who are just standing there like statues wasting everyone's time, but as long as they are trying to kill people I find yelling at them to be childish and dumb. The same goes for any other yelling at people who are trying to draw the other team into a favourable position for them in any other way. It's not anyone's job to make a round end sooner. It is just a courtesy to not wander around, stand on rooves, stand at the bottom of ponds and that sort of pointless garbage when there are 5 people left in the round and 80 other people sitting on their hands having no fun.