Sometimes kids who have great parents do stupid, defiant things. If it was indeed done by a kid or kids, I might wonder if a 10, 12, 14 y.o. Would contemplate the atrocities of the holocaust before impulsively scratching a symbol on a wall, or writing fyou or any number of things - like playing with matches. Parents can't, and I hope they don't, hover over their children 24/7. Consequences after the fact, of course. And, maybe it was an ignorant, mean-spirited adult who made the mark.