Let's be HONEST. The people on that video do not look average. They are universally young, attractive men and women. They look clean, well groomed, have beautiful smiles and even the 'right weight'. I won't say I would have kissed all of them in a heartbeat, because I wouldn't have (I don't kiss strangers, period). However, it's not the same thing to be asked to kiss a Hollywood bimbo (insert whomever you like) or the middle-aged man sitting across the bus with his belly hanging over his ill-fitting trousers and a smudge of something around his lips.
Plus, these people actually look good together. They suit each other in terms of good looks.
That said, the clip was beautiful and sweet, but not very natural. Either the kisses were staged, or everybody else kissing on the streets and public places does it the wrong way, because it normally doesn't look like that lol