Not a lack of knowledge mate, your friend was giving you the benefit of a doubt that you didn’t find “Rosa Park’s OnlyFans” so funny that you messaged him about it. As you’ve said, she’s a civil rights icon, so it’s pretty reductive to make a porn joke about her, especially when that… doesn’t really riff off anything specific about her. If it was at least a joke about “Harriet Tubman getting railed” (which would still be in poor taste) or something, you could call it dark humour, but the joke you shared is essentially “hehe girl nekkid” targeted at Rosa Parks. It honestly wouldn’t surprise me if the person who had that username was a racist and being dismissive of Rosa Parks intentionally. Probably not, I know how multiplayer lobbies can be, but it’s not a good look regardless.
He clearly knew who she was, he told you when he asked for clarification, and the timestamps suggest he didn’t have to look it up either. To be overly blunt, you don’t look the brightest that you’re so confident he’s an idiot for giving you the benefit of a doubt, when if you’d given him the benefit of a doubt, you wouldn’t be publicly embarrassing yourself trying to shame your friend. I’d assume that’s the cause of nearly every downvote you’ve received on this post.
Alternate recommendation (if you’re not already in Mod Organizer), I tried Amethyst Mod Manager recently, and it was fantastic. Full support for everything I used to do in MO2, even Jabberwocky lists. Bonus: it also has support for Thunderstore/BepinEx modded games, it’s a pretty darn impressive Linux-native all in one modding solution.