Biden was part of a meeting where the outgoing Obama team conspired to withhold information from the incoming Trump transition team, in particular that the Kislyak call appeared to be legit, a piece of information of profound importance. Biden was the one who brought up the Logan Act, then later lied, said he knew nothing about it.
I too would show Biden’s team the same disrespect that Trump is showing them. If anything, Trump is being too nice about it.