I mean to me it is just the old stereotyped masculine/feminine roles without saying it is masculine/feminine as there can be female initiators. It is more about who leads in dancing, and animation hand placements (I find it weird my flutter kiss (an ultra feminine feeling action) cups my male Sims head dominantly with their hand, and wish it was the other way round).
This is not a S&M or kink thing. If kids can handle gender transitioning, how they pee, if they lactate or get pregant, etc. in game, they can handle who leads in dancing, and where in game hand animation goes when kissing/hugging, and that gender is not it's identifier for it—at least IMHO.
Edit: This could also be helpful with same sex couples in game, which one is the lead in dancing? Which is the romantic initiator for animation hand placement?