We had the same advice from one of the cookware specialty shops when purchasing a non stick coated pan.
I initially took it to be a way to avoid warranty as olive oil is one of the regular oils used in Mediterranean cooking!
It was suggested by the store staff that the olive oil if over heated produces a burnt residue that sticks to the non stick pan and cannot be removed. Why this is unique to olive oil, and not other plant based oils makes little sense.
Stainless steel and cast iron cookware all requires oil and seasoning. We were directed to use canola oil on bare cast iron as it was less acid than other fats or oils. No answers here, just more questions?
