On Broderick, it was impossible to get going again on such a steep incline. It was also impossible to get back on the bike to ride back downhill, so I had to walk downhill and start over every time.
I didn't climb Fargo Street in LA. That video was from a male rider who lives down there. He is much stronger than me, judging by his other ride videos. I have a feeling he could make it up Broderick no problem.
I've never been to San Diego or the part of LA where Fargo Street is, but if I ever go down there I will seek out those steep streets you mention.
What makes Broderick so hard is the fact that there is no room to zig-zag. As can be seen from the pictures and video I posted in my OP, the wide sidewalk narrows partway up, so I could only do some half-assed zig-zagging at the beginning, not later on when I really could have used the help.