There may be no investigation of your specific question, but is there evidence of known dangerous chemicals. If it was covered in dog poop, would you use it unless there was evidence that the use of dog-poop-covered spatula at the exposure level of domestic cooking caused significant physiological effects?

A more fundamental error is say 'there's no proof, therefore I assume it's false'. There's no proof that it's safe either. We make almost all decisions without mass longitudinal studies.

And worse, IMHO, is the poison rhetoric: 'If I can shoot their plane, I'm smarter than the person trying to fly.'