The level of abstract monstrous stupidity to purposefully paint them black and leave them out there knowing you could be endangering lives?! My only good conclusion is maybe a local bike shop may have made a good few pennies out of the repairs.
You know what, i wish the person, or persons who did this the very best of luck because the kind of Karma that will come after them for this is unreal!
I don't understand their mindset but clearly they are just cowards.