Nearly everything doesn't give 100% accurate results. Even CPUs have had bugs their calculation. You have to use a suitable tool for a suitable job with the correct context while understanding it's limitation to apply it correctly. Now that is proper engineering. You're partially correctly but you're overstating:

> A tool that gives incorrect and inconsistent results shouldn’t have any part of a decision making process.

That's totally wrong and an overstated position.

A better position is that some tools have such a low accuracy rate that they shouldn't be used for their intended purpose. Now that position I agree with it. I accept that CPUs may give incorrect results due to a cosmic ray event, but I wouldn't accept a CPU that gives the wrong result for 1/100 instructions.