Tens of thousands of people waving rainbow flags lined US streets for gay pride parades on Sunday in coast-to-coast events that took both celebratory and political tones, the latter a reaction to what some see as new threats to gay rights in the Trump era. In San Francisco, a sign reading "Rise, Resist" was seen during the parade. Activists have been galled by the Trump administration's rollback of federal guidance advising school districts to let transgender students use the bathrooms and locker rooms of their choice.