"He is from Ohio and I was born there too. He is correct, at least in Ohio. We maintained the sidewalk of our corner lot because if anyone got hurt there, we got sued." Tell that to John Demjanjuk of Seven Hills OH. His sidewalk was littered with protesters for years.. and may still be.
Yes it is true that had one of the protesters fell and been injured the protester could have sued JD if the fall was due to lack of sidewalk maintenance.
The homeowner owns the sidewalk and is responsible for keeping it passable yet it is a public way. The homeowner also owns the "tree lawn" and is responsible for its upkeep yet the local govt has rights to its use.