Year after year every time a spray of starter fluid is suggested someone posts this kind of radical , untrue, the sky is falling ' warning' ....

A three second spray into the intake tube of starter fluid is not going to hurt the engine in any way. The proof is in the btu content of that compared to diesel fuel.

What is the purpose of trying to scare people year after year ?

The few documented stories of damage involve people putting liquid near the intake... not a propellant starter fluid introduced as the engine is turning over feet away from the actual bore.. and it can be very helpful in narrowing down what is causing the non start situation.