Earlier quoted context omitted.
Regardless of the original contract, it's entirely appropriate for a vendor to tell the customer how to use any materials. Imagine a _leaded_ pipe supplier not being allowed to tell the department of war they shouldn't use leaded pipes for drinking water! It's the job of the vendor to tell the customer appropriate usage.
This is quite literally the norm for things with known dangerous use cases. Go look at the package on a kitchen knife and it says not to be used as a weapon
No it isn't. There are warnings, but once a knife is yours you are free to do whatever you want with it, including reselling it to someone else. The idea of terms of service of using something is not something that typically exists with physical objects that one can own. They can't take your knife away from you because you decided to use it for a medical purpose without purchasing a medical license for the knife.