This is not a death nail in the coffin for Riordan. I support Simon, but Riordan is likely to win the primary. Keep in mind, that in CA, voters with no party affiliation can vote in the primary of their choice. So, most of the independent voters will likely choose a Republican primary ballot at the polls and vote for Riordan, as they tend to be middle of the road. End of primary - Riorday wins.
It is not the end of the story, however, as there is still an election to be run. So, these a-hole, old-fart Republicans are in the process of giving Davis a whole bunch of ammunition. Who is better - Davis or Riordan? The answer is Riordan, hands down. But these jerks cannot butt out of the primary. It is a Republican primary. Fine, come out and say you support Simon, but don't pee all over the other candidate(s) and make it impossible for yourself to then back that person if he wins the primary. Just the usual dumb Republican crap.
It is very likely that a majority of CA Republican voters have never even heard of these three chairmen. So their influence will be minimal. Still it is good to hear anyone say my favorite new refrain: JUST SAY NO TO RIORDAN!!!