The joke is that a pedophile lures a child into his car but doesn't molest or kidnap him. It's funny because you would expect the pedophile to ravage a child to satisfy his lust. That's how comedy works.
They're not trying too hard. As a matter of fact they're not trying at all for way too long. This joke could have been told in ten seconds and it would have been just as much of a failure.
I imagine this could have been an amusing joke with the right performances, camera work, timing, editing, and all the other things these guys got wrong.