I have occasionally killed animals for food. It wasn’t exactly fun, more like a little sad, so I made it as quick and merciful as I could manage. In my daily life, I avoid inflicting unnecessary pain, death, and suffering to living things, even earthworms or insects. And on the few occasions when I accidentally hurt a dog or cat, I got down physically closer to their level and apologized in a tone which they could hopefully get the gist of, even if they didn’t understand my words.
I occasionally say, “I can’t understand, and probably don’t want to ever understand, the mindset of someone who loves to brutalize and kill just for the fun of it”, but there are people who would call me a hypocrite due to being a practicing sadist. From my perspective that is not remotely the same thing, it’s purely consensual and for the enjoyment of *everyone* involved. I do my best to avoid permanent physical and/or psychological damage, and comfort them after. But there are people who see that as being little different than the sort of selfish cruelty demonstrated by the OP.
So I take a hard line against anyone inflicting deliberate suffering, for both people and animals (and even plants to a limited extent). It’s not because “I’m not as bad as *those* people”. It’s not about sacrificing “lesser predators” so that people will look the other way. It’s because the line is way too broad and fuzzy, and having killed and inflicted pain with purpose, I have more reason than average to draw a reasonably clear distinction between what is evil and what isn’t. As a result, even if someone like the OP is pretending to be a psycho just to troll people, or is genuine but doesn’t do it much anymore, I have to consider them a danger to others and treat them accordingly.