In the American justice system, the burden of proof is on the accuser, not the accused, and Orly has thus far not proved that Dunn is ineligible.
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.