TBK-Light.com

On the other hand, if there was a T1 pileup, restart, another T1 pileup, restart, another T1 pileup, race over, it wouldn't be fair to give points for such "race".
When creating the rule for non-points races, they had to draw the line somewhere. 2 laps of green racing isn't too much to be asked. I wouldn't personally award points for anything less than 10%. But when you start counting partial green flags and many laps behind the SC, it gets tricky.
It's also interesting that once you have done those 2 green flags, race director can continue the race under the SC for any laps in order to get full points. So we can end up having 2 racing laps + 50 laps behind the SC, and that's allowed, even though many would argue that full points shouldn't be awarded then.

The clause which states points will not be awarded if too few laps are completed under green flag running only applies to races where “the scheduled race distance is shortened or if a race is suspended under Article 42 and cannot be resumed,” the regulations note.