Comment by margalabargala

This isn't true, per your own link.

The point the Cleveland Clinic page makes is that seed oils tend to be what's used in ultra-processed foods, and those are bad for you. So if you avoid seed oils, you wind up avoiding the bad things as a second order effect.

Aside from that it's just hand-wavey "they use chemicals to make it! It doesn't have nutrients beyond the fat!". There's nothing to indicate that using sunflower or peanut oil is any worse for you than using walnut oil.

The connection between omega-6 fats and inflammation is a whole lot more tenuous than the link between ultra-processed foods and inflammation.