The problem isn't so much "When Blue goes high, Wingnut Red goes lower."
The real problem is that if Blue attempts to go lower than Wingnut Red, they run the risk of pissing off the same donors they rely on for survivial that also fund and enable Wingnut Red to go low.
Plus, that would risk retaliatory assaults from Wingnut Red exposing how Blue colludes with Wingnut Red to go Limbaugh low against IndyLeft (i.e., classic Red).