>>38187225For the most part, it's meant to be funny. Sexualizing anything that's not sexy or sexual - kids, animals, vehicles, etc. - is funny because it's absurd, and kids recognize that it's absurd, and most adults do too.
Though it's not an universal sense of humor, more of a cultural and recent understanding of humor thanks to years of social changes and whathaveyou.
Some adults, such as victims of child abuse, think of non-sexy and non-sexual things as being objects of their sexual appetites, so they miss the point of the humor. There's a market for perverts like this, just like there's a market for everything, because some people are greedy; they don't care about morals.
Most adults see this crap and wonder why characters are sexual and sexy in movies and other media, and they come to their own conclusions.
Granted, that's my own understanding of sexual shit in media thanks to studying humor and sexuality.