All "milk" comes from a lactating mammal's teat.
Therefore, all dairy products are derived from a mammal: cow, goat, buffalo, yak, elephant, etc. Many people cannot 'stomach' dairy products because they cannot get the thought of the 'host' lactator out of their minds ("milk is fine, but giraffe milk is just GROSS!").
What exactly are we objecting to here? All cheese is derived from "breast milk" - of one species or another. No one wants to partake of the same nourishment that we all had as babies?
(My mother was not a soybean, so I know what I was drinking for the first year or so...)