Did you know that doctor-germs are actually healthier than normal people's germs, and that hand-washing is all a scam by Big Soap. When I'm feeling sick, I just cut a small incision in me with a box cutter and have a doctor shove their finger inside.

So, leave your coworker alone! He's an expert in his field, and those aluminum and mercury particles are the healthy kind! Let him get back to spitting bread, tuna, aluminum-coated mucus, and epithets at his coworkers. Stop forcing him to intentionally misconstrue your cautions into personal insults against him!

Btw, this is the same reason that the exhaust from those giant coal-rolling vanity trucks is actually HEALTHY exhaust. And why I recommend that those drivers cup their hands around the tailpipe and gulp as much of their expertly-crafted emissions as possible!

Note: if you look really closely, you might find the part where I used sarcasm.