My mistake.I still think them dating was a bit creepy but I read those type of relationships happens more than I thought.
Joe brings his family into his campaign strategy- constant crowing about Beau Biden. As the weeks go by, he is/will be less interested in talking about "his son" because it will serve as reminder of the other one. Before long he will be into the "let's keep family out of the campaign discussion mode." Sorry, but it is not up to you now Joe.
So you think a democratic candidate on the debate is going to say "What about your son Hunter?" or that Trump is going to get up in front of a crowd and say "Biden's son is even creepier than Joe with his sister in law banging..." I doubt it.
Consider the possibility that many in the general public follow the media with the good, the bad, and the ugly in it and that it impacts their responses to polls and eventual vote.
Let's be honest, if Pence had pulled a similar stunt he'd be glorified as a good Christian for being a kinsman redeemer.
Sure if you assume 100% of all in the voting population who are not republican will vote for them. There are way too many people on the left who are more scared of socialism than Trump. With your relaxed attitude it is a given that Trump will win again. It is way more complex than you lay out.