The "omega-6-heavy oils" makes me think of the work of Dr. Nemechek (https://www.nemechekconsultativemedicine.com/nemechek-protoc...), who works primarily with Autism. He found that a variety of brain injuries that of various types (including things like concussion), which historically have resolved themselves, have, in recent years, stopped healing. So a concussion that would have naturally healed a few decades ago, keeps giving the patient problems. One of his primary recommendations is to decrease the "omega-6 to omega-3" oils, because it seemed that omega-6 cause brain injuries not to heal. And it's worth noting that almost all vegetable oils (canola, soybean, etc), which are in almost all "processed foods" are high in omega-6.

This indole-3 link could be the reason why omega-6 oils are so bad.

TL;DR: Don't eat processed vegetable oils (other than coconut and olive oil).