Way I see it, strigoi are like us with our humanity off. But, we normally choose to do that. To deaden the pain, and guilt for a while. I know about two people here who didn't choose it.
Elena, when she was sired to me, and I told her to. And Stefan, when Klaus compelled him. Both did things they feel guilty about.
Hell, I chose to spend decades humanityless and I feel guilty about it. But, I can handle it.