A word such as milk can be used to describe a variety of different substances. Mind you traditionally that substance has come from animals but these products are offering an alternative of similar nutritional value. I personally have never mistook a soy/almond product for dairy and don't think that banning the use of the word milk will create any type of positive change to the bottom line of dairy companies. The lifestyle choices that have made these supplements popular will still continue. Perhaps the dairy industry should look more towards ethical treatment of animals and the other reasons people choose to stop consuming dairy to begin with.
While often associated with a dairy source, the noun milk is ubiquitous for any substance created by way of its congruent verb, which means to extract or draw out. For this reason, one industry cannot have a monopoly on the word. Also, the other stated forms of the term have very similar qualities to dairy milk (such as cooking uses etc.), and are simply healthier.
Everyone understands that "milk" products made from soy, almonds, etc. aren't dairy products. They should still be able to use the milk label because they are milk alternatives. The dairy industry is trying to be greedy with the word in an attempt to limit competition, but it doesn't really matter. If someone prefers an alternative "milk" type, they're going to drink it. Removing the "milk" name won't change their minds.
I do not feel we need to be so literal here. Apparently the dairy industry feels that if it does not come from a cow, it is not milk. Well in my opinion, milk is simply the beverage we are accustomed to pouring out of the carton onto our cereal regardless of its exact origin.