But that's not the point. Gerrymandering is under control of state legislatures -- not contributors to viable House candidates.
One does not "refuse" to contribute money to an unwinnable seat. One sends one's scarce resources to winnable districts. If a winnable seat gets won by the opposition, the power of incumbancy could make it unwinnable in the future. This must not be allowed to happen.
Will Diana Irey beat the favored incumbent? I don't know. Ask me in mid November. Is it "winnable?" Yes.