I saw a video asking why the boys liked Powerpuff girls, with the underlying assumption of the video being that Powerpuff girls was actually intended for girls.

In the book Zen and the art of motorcycle maintenance, they talk about the concept of mu. This idea is that it doesn't matter what answer you give to a question, because the question is wrong. So in this video you are trying to answer the question of "why were the Powerpuff girls popular with boys even though it was a show meant for girls", and the answer is to unask the question because the question is wrong.

Powerpuff girls was never intended for girls, it was always intended for boys. It is right in the story of its creation, that the show creator put together a set of designs for their brother's birthday. The designs were not feminine to speak of, they were very male coded. Three girls who represent sort of idyllic fantasies of femininity (in 8 year old form) participating in wanton violence against monsters of the week.

This isn't a new idea, of creating a mythology of warrior women pointed at men. In antiquity, the story of the Amazons was essentially aimed at men, not so much women who don't care about fighting. In the middle ages, the story of Joan of Arc may have been empowering for women, but it was a story aimed at men. Japan being a modern civilization that has not yet fallen into postmodernism, quite frequently has women in their shounen stories, which are definitely pointed at young men, and of course postmodernism will always take the opportunity to subvert expectations, though I would argue that Powerpuff girls isn't necessarily a postmodern story since a lot of it's underlying superstructure is modernist in nature.

So at the end of the day, boys like Powerpuff girls because it's a well made cartoon for boys, not because they are somehow subverting expectations.

One of my favorite examples of this from anime which is a modernist art form, is the Rozen maiden series, particularly the first and second seasons of the first series. It felt very peculiar watching a show where almost every character is a woman, but when you look at the show as a whole it is clear it is almost exclusively designed for men, and the root message is about men.