Finally, humans Today easily get sick from eating meat less than ideally cooked.. Now go back thousands of years, wild, with low hygiene, no clean water, no clean utensils, no refrigeration..
You
do realize that evolution plays a large part in the diet of our species... Correct? We aren't the only species of humans to have ever roamed the earth, we just happen to be the only species from our clade that didn't go extinct. Thousands of years is plenty of time for the diet of a particular animal to change significantly. There are at least four distinct species of
Homo and to say that we were all opportunistic herbivores is just ignorance at best. The current list of known species and subspecies of humans include:
H. habilis, H. rudolfensis, H. gautengensis, H. erectus, H. ergaster, H. antecessor, H. heidelbergensis, H. cepranensis, H. rhodesiensis, H. naledi, H. sapiens (us), H. neanderthalensis, H. floresiensis, H. tsaichangensis
And to your "not properly cooked" thing that you always mention, humans are perfectly capable of eating raw meat. The only reason we cook our food is because of the transportation requirements. Fresh meat is far less likely to contain anything that would make us sick, but when you must transport it for hundreds of miles, it naturally picks up bacteria along the way. I eat rare steaks, because I like it that way. Humans also eat raw insects, raw eggs, etc. with little to no issues. Farmers drink fresh cows' milk that has not been pasteurized and they aren't dying. Humans have been eating raw and poorly processed animal products for millennia and will continue to do so for at least as long as we are alive.