Europeans have been cooking with flaxseed meal since before Alexander
the Great was born.

Olive oil is a fundamental part of the the Cretan Mediterranean Diet
which happens to be diet where the food is cooked.

Flax seeds and flaxseed oil are high in polyunsaturated fatty acids which
are extremely vulnerable to damage from heat. AFAIK, no transfats are
created, but heating oxidizes fatty acids which is harmful. It is best to
use flax seeds unheated or in baking but not in other cooking because of
this low resistance of heat.

Olive oil is quite heat resistant and is well suited to frying. Extra virgin
olive oil is high in phenolic compounds which gives additional resistance to
heat. Moderate frying temperatures are preferrable to higher temperatures.

All my ancestors cooked their fish in water, especially when
it had been salted and dried first. That's not high heat
compared to frying.

I consume most of my olive oil unheated - don't most cultures
around the Mediterranean?

I stand corrected.
John