Earlier quoted context omitted.
Sounds like the cyclist didn’t stop at the intersection or follow the rules of right of way.
I am usually one to bash cyclists for not following the rules, but I believe it's actually legal for them to do this at stop signs. They only have to slow down and check for crossing traffic before going through.
Even in places that do, they still require bicyclists to yield right-of-way to any vehicle stopped at the intersection before they arrived.