Because they're a lot less likely to kill me than raw milk is. Why is this even a question? People have literally died from pathogens they caught from drinking raw milk.
Who, other than people with allergies, has died from eating beans? Because as far as I know, cooked beans do not transmit dangerous pathogens. Raw milk can.
I was just giving reason, that exist to prefer raw milk. I only ever drank raw milk when spending vacations on a farm and i didn't buy cow milk since a couple of years.
Still i would like to say that i don't think raw milk is a problematic vector for pandemics to spread. Chance is people will get the shits if hygiene is bad, but i doubt a viral pandemic to spread because of raw milk. More likely would be farm workers getting an infection over the air and then spreading it to other humans.
A source that it's possible? You really need a source that something carrying viruses can be a transmission vector if it jumps to humans? Because I think you need to take a basic virology course in that case.
For starters i find it unlikely that a respiratory disease is transmitted through food. Possible sure. But by the logic of "possible" rather than "probable" we should never leave the house again.