Raw milk is another area where the FDA has it's head up it's behind. They state that raw milk can harbor dangerous organisms that can cause serious health risks to you and your family.
Unfortunately, pasteurized milk is not immune to harboring nasty bugs such as Listeria which has sickened and killed people. The Blue Bell ice cream fiasco in 2015 is one good example.
When raw milk is pasteurized, beneficial bugs as well as bad are killed off, so if disease causing organisms are present soon after pasteurization, the milk would likely become inoculated with bad bacteria. It's a process similar to making yogurt. You heat up your milk to kill off any bacteria, then add a yogurt culture to create a new dairy product. I've even made yogurt using live probiotic powder to gain the benefits of the healthy bacteria.
Under normal conditions with properly produced raw milk, the good bugs proliferate and raw milk is not dangerous to consume, except possibly by those with a weakened immune system, but even pasteurized dairy may be an issue for those people. Of course with any well managed dairy, continuous monitoring of somatic cell counts, salmonella, campylobacter and E.coli 0157:H7 is good practice.
Under certain conditions or production methods, the FDA disapproval of raw milk is valid, such as when cows are consuming unnatural feeds such as corn, especially GMO corn which is grown in association with Glyphosate. Use of antibiotics or rBGH are other inputs that would create raw milk that should not be consumed.