When it gets into the composition of cell membranes. Inflammatory and not conductive to good mitochondrial health which produces our energy. Phytocholesterol takes the place of a tiny amount of our real cholesterol (which is essential for life) and explains why lipoproteins (the so called cholesterol) go down when consuming plant derived oils.

That is the theory and the mechanism proposed as how it is harmful. Or at least some/one of them. I'm no scientist nor doctor, just a dumb high school educated retired dirt farmer that watches way too many Youtube videos on the subject. So I don't know.

Keep buying the soy and corn oil. Thank you. Canola? Meh. The Canadians will have to encourage you to do that.