Why are premades such A holes?

Played a normal game where a premade of 3 went top, mid and jg. Me an another solo player went bot and we were losing the lane.

I asked the jg to gank bot lane but he kept camping at mid and top and ignored bot lane

They complain about us not doing good yet none of them would help.This isnt the first time it happen but i dont understand why they were so rude.

They didnt ping

They didnt type or communicate

They didnt even go near bot lane once, not even to get dragon I dont get what they gain by ignoring other lanes and not helping out