This has always struck me as a dumb argument. Before “intellectual property” innovation was just technological advancement. Patenting is just enabling punishment against actual innovators. I am a welder. I make things. If I set out to make a stove, I don’t give a shit who patented what fuel distribution system or air intake methodology, I’m gonna make a damn stove. The entire concept of being able to exclusively “own” a design or concept is reductive to human learning as a whole.
Welder here. Aluminum oxide inhalation is correlated with an increased risk for alzheimers, not cancer. Hexavalent chromium is a carcinogen, and that comes from heating up stainless steels. So you are actively replacing a relatively non toxic oxide with the potential for an actually toxic carcinogenic gaseous metal, assuming your pocket knife is some sort of stainless steel (statistically very likely).