Well, I don't hate Sasuke but I understand why some people separate Gaara from him:
Gaara mainly killed people that attacked him first or were enemies of his village (as the Sand village was planning to attack the Hidden Leaf).
So his actions while wrong, were more along the lines of warfare (but even then that is pushing it as he did commit crimes).
Sasuke ditched his village, attacked and tried to kill someone who considered him his best friend, attacked a village that the village he came from was at peace with, killed a Hokage candidate (yes he was a amoral jerk but that doesn't change his position), stabbed and almost killed Karin who trusted and loved him, abandoned Suigetsu and Juugo two people who considered him a friend and comrade, attacked the five Kage summit on behalf of a terrorist organization who he was aiding, killed many Samurai who were just doing their job when he could have dealt with them easily without killing them, helped revive the Ten Tails by delivering a tentacle of the 8 tails, and tried to destroy a village that his brother sacrificed everything to protect.
There is a vast difference between Gaara and Sasuke, yes Gaara did horrible things as well but they pale in comparison.