Devore never really got into the race, he has stayed about 20 points behind and his campaign seems to have hit the skids lately, he is not going to suddenly leapfrog over everyone and make up the 20 point deficit in the next few weeks, especially as the big money comes out in these last four weeks.
California conservatives desperately want to keep Tom Campbell out, Fiorina is the only one that can do that.
To answer my own question: The best argument I've seen "against" DeVore is that his campaign war chest isn't nearly as big as Fiori-bell's. That's a "sad truth" that carries some weight with me. And I can agree that it is a shame we have three big candidates instead of two (creating a risk of Campbell getting a plurality). Still voting for Chuck.