Here in the UK, animal fats disappeared from the ingredients labels of most commercially-produced cakes and biscuits a good fifteen years or so ago.

There was no great upheaval. I thought at the time that the number of vegetarians/Muslims/Hindus who avoided such products must have reached a critical level where the manufacturers cared about the loss of business.  More realistically, it's possible that the abolition of the practice of rendering (boiling up the carcasses to get the last scraps of meat and fat) post-BSE reduced the amount of cheap animal fat.

(I realise the hydrogenated crap with which it was replaced is no better in health terms...)

However, last year Mars announced that it would be using slaughter-derived whey in its chocolate, and was forced to back down after a week.  So...is there some quirk of labelling that allows decaying fish to be labelled as vegetable oil, or does the British situation, though equally nutritionally icky, not involve the more emotionally repulsive ingredients?