Maybe the cyclists don’t like the stop signs that the path frustratingly has but the road does not? Around that stop there are two within a few hundred metres, and frequently stopping (or slowing down fot a rolling stop) makes riding slower and more tiring. That’s probably not nearly the entire motivation, though.

The US Supreme Court then reversed the Ninth Circuit ruling. You’re quoting the background that gives context to the case in the lixned article.