I have mixed feelings. On one hand, I think it's absolutely silly that I go to the club and seen a dozen dudes dancing without a shirt on, whether anyone likes it or not, and it's no harm, no foul. No one thinks twice. I really wish women had the freedom to do the same, because I love being nude and I don't see anything inherently sexual about human chests, female or male. But that's not the world we live in.
HOWEVER, the larger part of me feels like this video and the flashes were done in an intentionally sexual manner. It was done in order to titillate and flirt and excite, which takes something natural and sexualizes it. Which is where the consent part is important, and why one should always honor another person's consent.
To go out of your way to ask someone's permission, and when they ask you not to, to purposefully violate their consent anyways... That's pretty shady. I mean, even sexuality aside. This goes for any situation. If I asked someone if I could hug them, and they said no, it would be horrible of me to hug them anyways. It is invalidating their consent, and putting my desires above theirs. Adding in public nudity done in a titillating manner - and I feel it does cross the line to sexual harassment.
Even if you believe that the human body is natural, and nudity isn't sexualized... It's important to see things from the views of others and respect their personal boundaries. Flashing people against their will is NOOOOOOT the way to go about changing societal views. Violating consent & sexual harassment is not the way to change the world. Even though I personally see nudity as natural, I still would be super offended if a man flashed his genitals at me in public, especially after I already asked him not to. It isn't the nudity itself that is offensive in my eyes - it's the invalidation of my consent, my emotional comfort. It feels like a twisted sexual power game. It's his desire or his thrill becoming more important than my comfort and personal boundaries. And this situation feels the same.
There are spaces where being topless in public is allowed, and where people have the choice to view it or not, to stay or go away, and usually, those spaces don't involve sexuality (i.e., nude beaches, topless bike events, slut walk protests). The places where nudity is sexualized are usually privatized, i.e., strip clubs. People go there INTENDING to see sexualized nudity. To go to a space where public nudity is (I'm assuming) not allowed, and draw someone into a sexualized situation AGAINST their specifically stated consent... I can't think of a single situation where that is okay. It's not. It's assault.
Nude laws and spaces aside, it boils down to this. It doesn't seem right to go into someone else's space, ask their consent to involve them in a sexual situation, and violate said consent when it is refused. Anyone should have the right to refuse sexual situations. Especially this poor dude. He just went to the club to have fun, to dance a little, to drink a little. He had his consent violated, and became the butt of jokes on the internet.