Not shedding tears for all of Rumple’s life, as an adult he made terrible and bad decisions. A tragic, traumatic childhood can explain but it doesn’t excuse / justify behavior IMO. Rumple killed a man just because he yelled at Bae, and he killed their maid because she might haven been able to somehow give away the secret of the dagger. These killings were not tragic for Rumple but for the people he killed and their families. With the magic at his hand Rumple didn’t have to kill these people, but he did, and even seemed to enjoy it for the moment. Rumble might find redemption, but he did terrible things all on his own (and no, the Curse of the Dark One doesn’t excuse it for me either, he still had an idea of right and wrong).
He knew the difference between right and wrong and he chose the path of power and that’s why he, in the end, had to make the ultimate sacrifice (but he’ll come back) to make his way down redemption road.