Were all five loose lugs on the same wheel? I have to imagine it was just one or two being loose initially, causing the loose wheel, which over several laps would cause the other lugnuts to loosen as well. I wouldn't be surprised if the wheel studs were bent.
Losing the stage points is what bugs me. It makes no sense and sets a bad precedent. If the lugs are loose enough that the wheel comes off out on the track, does he still lose the stage points? What if he walls it on the frontstretch as he crosses the finish line on the last lap, does he still get the penalty?