Of course producers influence it, that's their job, they need to keep it interesting or it would just be a bunch of folks sunbathing.
But the actions are all the contestants and they vie to go on there. They know exactly what they are getting into and want the fame. The good bits of it. And they get bitter when they don't get it, or it wasn't as good as they expected, they didn't turn into the stars they wished to be, let's not pretend otherwise.
It's people like Amy I don't understand, she's 26 years old. She knows what that show is, you don't go on there to find a life partner. More a holiday romance with a shot at fame.
If you want a life partner, then there are many ways to go about it. Appearing on love island isn't one of them.