I was watching people spewing that “operating” versus “driving” bilge go to jail thirty years ago.
Still, you can find plenty of modern statutes that state "driving or operating", or have different sections relating to motor vehicles, stationary engines, and so on.
I would imagine some state laws were slow to get into line with the modern sense of words and the understanding of what was going on. Obviously a vehicle in a garage being subjected to maintenance isn't the same as a vehicle on the highway ~ but in both cases there are environmental laws that require adherence to the same standards, plus OSHA has a whole great big pile of regs about maintenance.
Then you should have done something to intervene.