I can't speak for everywhere, but in Michigan pedestrians have the right-of-way at all marked and unmarked crosswalks, an unmarked crosswalk being anyplace it would be logical for pedestrians to cross, i.e. a parking lot directly across the street from a big building, etc. Lights are for their safety, not to enforce when or where they can cross.

OTOH, bikes are given all the rights and responsibilities of vehicles. Vehicles are not pedestrians, and that's where the problem comes in: too many cyclists consider themselves 'pedestrians on wheels' rather than 'human powered vehicles.'