From your link:
"Taitz has also said – and a pending civil suit by a Taitz backer reiterates the claim – that Dunn's candidacy violated the requirement that a candidate not be registered with a different party for at least 12 months before filing to run...
[You forgot the prominent part of the article in bold]
...A district attorney's spokeswoman said Taitz's complaint was "unsubstantiated" and the case dropped."
No one really expects California office holders to do the right thing and investigate.
The lawsuit by Barnett simply reiterates the claims that were deemed unsubstantiated by the DA.
There’s nothing disingenuous about assuming that the court will share the DA’s opinion. It’s common sense.