In the past Lowe tried to molest Victor but he got overpowered by the pheromones..it's not that he hates omega but js loves to dominate them...but since Victor overpowered him..he wanted to make a drug so that he could see Victor be completely defenseless...pretty disgusting..he deserved to be tortured more before dieing..but atleast he's dead..
The cousin had superiority complex being an Alpha himself. He looks down on everyone especially omegas. He wanted to molest Owen, but owen instinctively fought back with his pheromones, Owen is a dominant Omega that's how. Freaky cousin suffered a mental shock because of the massive wave of pheromones from Owen. If it makes sense, maybe exposure to threatening levels of pheromones overloaded his biochemistry in the brain and his nerves fried form the stimulus. Freaky cousin woke up in the hospital with wounded pride, and his obsession over owen and trampling over omegas was firmly established when his attempt to molest Owen backfired with a permanent ED. That's why we can only see him getting off on watching omegas suffering with overwhelming arousal during his experiments. Since then, he obsessed over dominating Owen. Nick was right, Freaky cousin had always have that sadistic tendency in him, it was fully awakened to the extreme after what happened with him and Owen, and his parents spoiling him helped nurtured the monster he is.

Help me understand, why does he hate omegas so much? I was confuse if the accident with owen was just the only reason? Or did I missed something? But then again lunatics don't have the same reasoning as a sane person