This is total nonsense.
Imagine the hotels, establishment bathroom stalls, and other
places now liable for a women catching an STD from a one
night stand.
No one takes personal responsibility for anything any longer.
Doesn’t work like that.
She claimed he negligently transmitted the disease. So she sued the man.
His insurance company owed him indemnity because the negligence arose in relation to the use of the vehicle, just like if he hit someone with it.
There are loading/unloading cases like this with drill pipe (pipe falls off truck when loading because someone was being an idiot).
His homeowners’ insurance probably would pay, too, if he nailed her at his house, just like if you negligently harm someone in your house.