I’d argue that isn’t even dark humor. The joke’s focal point is how ridiculous that position is. You’re taking up an untenable and patently absurd position in faux support of the initial absurd position. That’s ridicule. Now I will grant that lampooning a rhetorical opponent’s position can lean “dark”. Unless the punchline relies on taboo for the heavy lifting though it isn’t crossing that line.

You didn’t say anything offensive or taboo. You criticised someone’s bad take using contemptous analytic hyperbole. I grew up with this kind of humor in my family. It was mostly used as a learning tool which avoided direct confrontation of idiocy while allowing the temporarily embarassed idiot to save face, realize they weren’t thinking clearly, and choose to be in on the joke at their old self’s expense. There are other choices, or course, but if you chose to die on mount stupid then you’d better expect to get buried underneath it as well.

Your family doesn’t seem to be receptive to that brand of social therapy. That’s ok. My point is more to encourage you that you didn’t do anything wrong (and that it’s even normal to joke like that elsewhere).

Your mom might not think you’re funny… But I do!