What are those really ugly trees all over San Francisco

They appear to be Sycamores. (I'm looking on Google Street View at the ones along the street in front of City Hall, and then the ones along Lombard Street left and right of the entrance to "Lombard Place.")

Pollarded London Plane trees?

You mean the ones in 'Invasion of the Body Snatchers' (1978)?

Pollarded Sycamore trees.

Mexicans?

As much as. I like San Francisco, they get. a D minus for public tree maintenance….

Sycamore trees can live to be 400 years old. There's a massive one near a river not far from me.

Look up pollard!

The pollarded trees near SF city hall are sycamores. Many others exist in the Bay Area: Berkeley is famous for its pollarded London plane trees—they are extra cool when you’re tripping on mushrooms or acid. 😵‍💫