I thought they can label things as 0g Trans fat or even not list it so long as there is less than .5 grams per serving.

Looks like my thoughts were somewhat correct, at least at some time (August 2003 until ???), scroll to #6:

http://www.fda.gov/Food/GuidanceRegulation/GuidanceDocuments...

EDIT: typos

Right, and you can read it on the wall of any fast food restaurant... but tell me when the last time you've seen someone read that. It's fair for regulators to take into account people's actual behavior.

GP claimed it was "slipped in unknowingly" which is false. Anyone who has paid any attention to the media the past few years knows that trans fat is now thought to be bad (never mind that in previous decades it was considered to be healthy, or at least "less bad" than saturated fat).

I actually do look at trans fat content on the labels quite often. The labels are very simple, it's not like a terms of service that's highly verbose and deliberatly obfuscatory.

If you want to avoid trans-fat, it's trivially easy.

The same thing can be said for alcohol. These facts aren't hidden.

Sure, but there are tons of products that list '0 trans fat' while also listing partially hydrogenated oil in the ingredients. The FDA allows a certain amount of trans fat while letting the company claim 0 trans fat. Then the Bloomberg article says "The FDA said it hasn’t seen any data to prove that even low levels of partially hydrogenated oils are safe."