The marmots of the Sierra are specifically yellow bellied marmots and live specifically at higher altitudes in alpine terrain. Groundhogs are also called "marmots" and are of the same family, but different species and live in lower wooded areas.

The Sierra marmots aparenty have trouble getting salt. There destructive behavoir is a result of trying to get salt - pee on the ground and they will dig it up, salt on pack straps and trekking pole straps are sought after, as are car tires (people on the coast have salts on their cars simply from the sea air). I do not think their behavior is simply a result of interaction with humans. There are lots of marmots for the ecosystem and probably too many- so they ar forced to aggressively go after human food.

I have thrown rocks at marmots. They seem to not have a clue about it. It appears they do not connect my throwing a rock with the rock that hits them. They do not get the idea of a flying projectile. But if you run towards them or kick them, they scurry off, but only for a while. They carry diseases, so I would not want to handle one.