because lefties pushed forward "Open Primary" laws the demcrat party doent really choose their candidates via primary, except where required by law. democrat primaries are really a straw poll, which is non-binding. so the party that doesnt actually let the people vote for their candidates can use their otherwise pointless vote in the democrat's fake primary systems to pick a shitheel for their pre-selected candidate's republican opposition.
in california, the primary system has been abolished, and everybody gets to vote for a candidate, and the top two vote getters are the candidates in the general election.
net result, many races will be democrat v democrat, which may be lulzy, but when they implode or they are arrested for selling anti-tank missiles and machineguns to undercover FBI agents, we are left with no election, just the slightly LESS crooked winner by default.