It is mesmerising, in a kind of going to the zoo way, looking at the strange creatures you wouldn't usually mix with I came on to say this!
Of course its utter tosh and the people are not the type I would be friends with, but actually they become quite endearing when you watch the whole season 
They're not necessarily hamming it up either, this is how they behave in real life (check their initial photos, always out clubbing and pulling - thems were the days!)
Quite a few of them do end up in reasonably long term relationships from it (obviously there is some Instagram mileage for them, much like many sleb couples) so its not entirely about just winning the show.
I agree its not for kids but the most you really see is some blankets moving about with blurry night vision cameras - most teens will sadly have seen much worse online.
Seeing these people treating each other as prey or as disposable might actually be a bit of an eye opener for young people. Realising that these people will say one thing to their partner's face and another to camera makes it compelling TV but is also educational - I'm sure a lot of the girls watching will be a lot more cynical about the motives of any 'grafter' they come across! And no, my DCs don't watch it, but when they're older I won't judge if they do.
I know plenty of people who enjoy shit TV, whether Gogglebox, I'm A Sleb, soaps or this. Different strokes and all that.