American here. Can't speak for anyone but myself, but I've always seen adulthood as the culmination of my loss of freedom and the beginning stages of the rest of my life as a laboring drone. I didn't actually enjoy much of the first decade of adulthood because I spent the whole time surviving a system I simply am not built for. Now that I've made it through those harder bits, my body's starting to wear on me, and I'm not really able to appreciate life like I could have under more accommodating circumstances. It's hard not to hate adulthood sometimes. The pieces of me that are still childish are kinda the few remaining parts of me that can still experience joy, barring the moments where others make me feel pathetic for still being childish as an adult.

That said, I agree that the baby voice and daddy stuff just...doesn't do it for me. I try not to yuck yums, and I know the world of sex is as complicated and diverse as the humans who engage in it, so I'll just say it's not for me and leave it at that.