Hydrogenation, by the way, has little to do with trans fats. Hydrogenated fats are saturated fats. Trans fats are unsaturated, and have a trans double bond at some point in the hydrocarbon chain.

This is where your argument breaks down. You've forgotten several key points that make all the difference.

Hydrogenation has little to do with trans fats? What the hell is this statement? Let me fix this for you:

A trans fat is an unsaturated fatty acid with a trans double bond instead of a cis double bond. The fatty acid loses most of it's flexibility and it's ability to kink, a critical characteristic of fatty acids. These trans double bonds are characteristically created by industrial hydrogenation of vegetable oils. There are no two ways around it. All industrial hydrogenation creates, by very merit of it's process, trans fat. There are no alternative methodologies, there is only hydrogenation which creates trans fats.

then non-hydrogenated margarine should be reasonably free of it.

Margarine, by it's very definition, is a product composed of hydrogenated vegetable oils. If you do not hydrogenate the vegetable oils, they do not saturate. It is not margarine, it is a cup of canola/soy oil.

There is no such thing as "non-hydrogenated" margarine, and I strongly question that current margarines do not have any trans fat in them.

By loophole of current FDA regulations, ingredient lists can be rounded. Thus, "0g of trans fat" only literally means "<0.5g of trans fats".

It is completely legal to have 0.49g of trans fat per serving and write "Trans fat free".

If you think I'm wrong, go look at the serving sizes of "trans fat free margarine". They are generally tiny serving sizes meant, in many cases, to lower the amount of trans fat per serving under the requirement.

Margarine is made of hydrogenated vegetable oils, a process which creates trans fats. They can never escape that reality without literally changing the fundamentals of what "margarine" is.