Not really, it's more because of gerrymandering. Throughout California and even in Berkeley, Democrat representatives are way, way to the left of the average voter in their districts (and the Republicans way, way to the right - thus the existence of a Duncan Hunter) but they stay in office because the boundaries as drawn virtually guarantee a party victory and a perpetual Democrat majority. It takes an awful lot of radicalism or malfeasance in office to get a politically disinterested moderate to stop voting their traditional party allegiance in the voting booth: "Oh, yeah, I remember Barbara Boxer...she cares about the environment. Check."
Redraw the districts in a more natural manner and there would be a lot more close races.
Gerrymandering can only go so far. If your overall vote is running anywhere from 75% to 85% for the bad guys, you’re not going to get a competitive district out of it. Take a look at another example of a moonbat state, Massachusetts. Of the 10-member House delegation, we couldn’t gerrymander for ourselves a single Republican seat. At best, we might be able to get one in which we have a 40%+ shot at winning, but no better. San Francisco, Marin, San Mateo, Alameda, most of Contra Costra — they’re virtually all out of reach now.
Remember, too, that the post-2002 Congressional lines in CA are effectively little changed from the post-1992 lines, essentially incumbent protection, which were favorable to the GOP (and at one point, we had a tied delegation in 1995 following Tom Campbell’s special election victory, 26 seats each). Aside from a couple seats, virtually all the counties that vote majority GOP do have GOP Congressmembers.