Is there a stated rule against doodling on projects? Would 15 points have been deducted for random swirls or flowers? What about a random scribble to get the ink going on your pen?
I think the teacher is out of line, and I hope your DS stays quirky! FWIW I kinda regret how much time I spent talking my older DD out of being weird and wish I'd spent that time instead talking other people out of being uptight. Yes, you have to learn about appropriate behavior for certain people/situations but, come on, that's nothing on the weirdness scale