Subject: Re: You can't handle the truth
What’s with all the policy wonkery? Why didn’t Joe Biden talk about the scary sharks, the batteries, Hannibal Lecture and what a fat pig Chris Christie is!

Different audience and different goals.

Biden's in a formal policy setting trying to convince people he's still technically sharp.

Trump's at a pep rally reinforcing to his base that he and they are part of the same in-group by using a lot of references to things they mutually understand and care about. That strengthens the bonds they have with him.

Ironically, the more the out-group attacks his use of those references, the more effective his rally becomes at achieving that goal. It just reinforces the message he was trying to convey, which is that Trump is a part of the in-group with his voters and his critics are not.