First the poem …
I've seen this kind of commenting behaviour time and time again and for far less atrocious acts …. or attached to items like all those Walmart posts, … condemnation offered up for nothing more than having a questionable fashion sense. So what that tells me is that the comments are not about the act but rather a chance to serve the ego through anger and/or exercising a false sense of superiority.
How can I give empathy to a monster ...
Whether you come down on the side of nature or nurture ... until we learn to transcend our own fear, lust, and anger ... we are a combined product of our DNA and environment. We have no control over our genetics and when we are young, we have very little control over our environment. Given the same DNA and with the same upbringing and faced with the same situation, you would behave the same way. Don't kid yourself otherwise.
Seriously ... we've been condemning and judging for millenniums.
In the end your judgement does little to help the situation, has a negative effect on you and the one's around you, and prevents learning and increased awareness. But just in case you needed some more convincing … here's one more poem