Jothar,
Thanks for that source. It’s possible that some people died after drinking milk, but it’s very unlikely that “many” people died due to lactose intolerance, unless they were already near death due to famine. It’s also possible that some succumbed to the germs in the water used to reconstitute the milk from powder form. The wikipedia article you quoted did not mention any deaths attributable to lactose intolerance, and indeed the scientific consensus is that lactose intolerance can cause great discomfort but not death.