Trying to answer what I think is the most reasonable point you’re trying to make: supply chain extends beyond you and your actions.

What if you were distributing food, and a farmer who supplied rice to one of the manufacturers of the components of your food grew that rice on a field that was contaminated with arsenic?

If you will get bad food, who are you going to blame? Very likely the person who you get the food from, not going up the supply chain like a detective.