Why would you want to kill all the microorganisms in your food? Do you drink purell to get rid of all your gut microbiome? 

If you’re gonna drink water from a dirty pond then it makes sense to boil it first. Water from a glacier is probably fine to drink as is.

Same applies to food. If it’s low quality and dirty then cook it. If it’s of great quality and pristine then it’s fine to eat raw.

It’s not rocket science. Just common sense