you might be right, you should collect more data points, try this class of jokes out on more people and see how funny they find it, you could call women walking birth canals. It should be easy to formulate this comedy; take a broad category of people based on some immutable quality, like skin color, find the least charitable insult you could possibly imagine, like parasite, and see how funny they find it.
I'm ~60% sure they themselves are trying to bait someone, into an anti-abortion argument. They're definitely deliberately taking the most provocative stance possible, and trying to provoke more people along with them.
edit: re-reading their comments, I'm at least 80% sure.
Possibly. People tend to speak more callously on the internet than in real life, but I asked a few coworkers about this, all were uncomfortable and one was visibly distressed; I guess thats what happens when someone that hasnt experienced this kind of behavior growing, then suddenly gets a full dose. Its hard to imagine winning anyone over leading with that.
Though, the strategy isnt so much about winning in that arguement, but just trying to get an ugly response, so you are probably right.