Yes, humans died out 7,500 years ago when cow's milk was introduced to the human diet in Central Europe. The species never recovered.
It amazes me what ignorant f%#tards there are out there freaking out about things humans have safely consumed with 7000+ years of epidemiological evidence ... and yet they'll think nothing of ordering a Jamba Juice with some mysterious "Antioxidant Boost" that was only invented a few years ago.