Dont let that guy get under your skin.
I worked my way up through the trenches before I ever got a piece of paper that said I WUZ Certified to work on HVAC equipment...
Guys like that came out of a class room without a clue and yep... They know everything.. Just ask them...
Im with you... Experience and common sense is far more valuable..
Dont stop advising people.. You are correct in everything you said. And I am a degreed engineer too.. But I came up through the ranks..
If Drew feels he needs to attack you it is because of his own insecurity and a lot of arrogance... That wont take him very far in life. But he will learn in time. hopefully...