It's weird how almond, soy or coconut liquids can legally be called "milk" none of those sources have nipples. Coffee is liquid from fermented beans similar to soy it's no more milk than soy is.
I know here in Canada for decades margarine had to be smuggled into the country, when it was legal it couldn't be yellow like butter (but even butter has artificial yellow colour added), it certainly couldn't be called butter.
They can be called "milk" legally because the definition of milk includes the whitish fluid produced by plants. The dairy industry has tried to argue against its use "to prevent consumer confusion" to no avail: http://www.motherjones.com/blue-marble/2010/04/dairy-lobby-t...
Lewis Black said it (ranted it?) better: "There's no such thing as soy milk, okay? And I know that because there's no soy tit, now is there? I don't know a lot, but I know you need a breast for milk."—Rules of Enragement, "Ireland and Health", 7:04-7:11.
I don't think it was anticompetitive reasons although the end result was that I believe it was farmers created a market for butter that margarine would benefit from.
IIRC, some U.S. states (Wisconsin might have been one) had similar laws. The margarine companies used the workaround of including a separate food coloring packet, which the customer could mix in at home.
It's not about defrauding anyone in this case: Margarine looks disgusting without added colour. Even if you prefer margarine or have made a fully informed choice you might still very well prefer to add colour to it before using it.
The reason for laws restricting colour additions to margarine was explicitly because it is sufficiently close to butter in taste, texture and usage that it created a substantial competitive pressure on butter sales because people would happily pick margarine over butter to save money. So much so that the separate coloring failed to stem the growing demand.
I know here in Canada for decades margarine had to be smuggled into the country, when it was legal it couldn't be yellow like butter (but even butter has artificial yellow colour added), it certainly couldn't be called butter.