You're asking candidates to compete for a job. Why are you surprised when they take actions consistent with their best interests. I don't think Schiff did anything inappropriate. Schiff mentioned Garvey to raise his profile because he's easier to defeat.
This isn't like Nixon contacting South Vietnam while he was a presidential candidate and telling them to not make peace because he wanted the war as an issue. That directly led to the deaths of thousands of Americans.
Assuming you preferred Katie Porter, what did you do to ensure she'd be the candidate?
Someone needs to be at every one of his campaign events shouting, "Pay your back-taxes! Why haven't you payed your taxes?" at full volume.
Edit: When someone like this is on stage supporting your campaign, you know you're evil as fuck.
Edit2: I landed on his site trying to find out if he'd have any events that I can drive to and take my own advice. I found no info. I live in the Bay Area. If you find out he's doing an event that I could drive to in an hour or less, please let me know.