It is not milk (from biological and legal points of view, only mammals produce milk). But, logically, it is better to present a cockroach secretion as "milk" if you want to convince people that it is a "superfood" they can eat.

Studies show that the nutritional profile of cockroach secretion is interesting, but human beings eat food (nutrients & symbols, etc.). From a marketing perspective, insect secretion must be milk to be good to sell.

No insects produce milk sensu stricto because they lack mammary glands, a defining feature of mammalian lactation. However, species like tsetse flies, certain cockroaches, lice, social insects, and earwigs produce nutrient-rich secretions that functionally resemble milk by nourishing their young or colony members. These cases highlight evolutionary convergence, where insects have developed analogous strategies to provide parental nutrition.