The median temperature in midwinter isn't really that different between the Willamette Valley and the Sacramento Valley given the latitude difference - this is when the N/S gradient is generally at its lowest. The extrema, however, are very different - the cold snaps in the PNW are much more severe (Dec 2013 in Eugene is impossible anywhere in lowland CA) and the warm end potential is usually much higher down south due to more downsloping and lower latitude.
I agree that there's a double standard. Trump hasn't put a whole lot out there in terms of policy, but I think he gets the benefit of the doubt with more people since he's been on the national scene for longer and been president before. I also wouldn't rule out there being some element of sexism going on as far as this goes... like if we had the exact same situation with a male nominee swooping in to replace Biden, I'm not sure there would be quite as much talk about this. Can't say that for sure though.
The process with replacing Biden with Kamala was so rushed... I mean it was only 3 months ago. It takes a long time for people to really get to know a candidate and their positions and for that to seep into the collective consciousness, and Kamala lost out on time. She also just doesn't sell herself that well and has a problem answering some questions as others have pointed out.