There's a HUGE difference between lying and calling something by it's generally accepted name where the product is more that ingredient than not.
Do people truly believe your Hershey's chocolate bar, despite being called "chocolate" is 100% chocolate? Nope try 45% to 60% cocoa (actual chocolate) even for dark chocolate.
Is your aluminum Macbook or laptop 100% aluminum despite only being called aluminum? No, more like 90% aluminum and has nickel, iron, and other metals in it.
As the video said, it is more aluminum oxide than anything else, so calling it sapphire generally is not incorrect.
Being 100% sapphire and that thin a part would be INCREDIBLY brittle and shatter in 1 drop. Being harder can make things more brittle; not always a good thing. There has to be some compromise in an alloy form to achieve decent scratch resistance and decent drop/shatter protection.
None of this is altering anyone's life so significantly to spend hours on the internet complaining about it. The video even said the 6 and 6S line is the same material and no one en mass complained about lens scratching.
If it is that big a deal most here are still within the 14 day return period. By all means.