I can see both sides. It's clearly physically harmless but it would cause psychological trauma.

First, let's acknowledge no-one is calling the man a man, he's unanimously called a kid or a boy. That, as well as what is listed in the comment above, is an indication something, besides the intended sexual intrigue of the porn connoisseur, is wrong.

Now let's address that it's from porn. Absolutely no-one is holding the financier and facilitator, possibly just the camera man but more likely the camera man and a whole lot of financial aides, in this video responsible. Honestly, it seems as though the lens is mistaken for our own actual perception. We just happen to see some depravity.

While the actress is responsible for her actions, her actions are greatly being incentivised by an actual pervert. This is the corollary to the male flasher argument: they are doing it for themselves/sexual gratification. The actress is doing it for money.

The breasts as a sexual object is an interesting argument but I wouldn't say it was the crux of this issue.