SAN FRANCISCO — Like huge lumbering beasts, the luxury buses shuffle down Valencia Street.

One by one, they stop in front of a hipster coffee shop. Bearded young techies swipe their IDs as they board, clutching cups of premium coffee. One fellow carries his dirty laundry. No one talks. The buses take off for the campuses of Google, Apple, Facebook, Yahoo and eBay.

It seems like a mundane commuting scene. But it is not. A security guard hovers. There might be trouble.

Even as the tech companies extend their global reach and jostle to own the future, their hometown is turning from admiration to anger. The buses, which illegally use city stops, have become an unlikely rallying point. First, people were priced out of their homes, activists say; now they are being pushed off the streets.

Demonstrators regularly block the shuttles. Last week, a group of activists stalked a Google engineer at his East Bay house, urging the masses to “Fight evil. Join the revolution.” A prominent venture capitalist struck back, comparing the tech elite with persecuted Jews in Nazi Germany.