That is true for meat like chicken and pork which absolutely have to be cooked through. Eating that meat raw is almost certainly going to lead to food poisoning.
Beef is probably about the only meat which is very safe to eat rare though. The point about bugs and viruses I made earlier is correct, it can't get inside the meat only rest outside on the area which is cooked so the bacteria is killed by the heat. The things which you might have to worry about in beef are things like tapeworm etc which can reside inside the meat but if you take a good cut of beef eg a fillet steak from cows which have been well bred and looked after then that risk is negligible too.
I have been eating my scarily rare steaks regularly for years now and I have never fallen ill from one.
Well, things like chicken naturally have dangerous bacteria like salmonella. Although beef does not have that particular bacteria naturally, it still has some that CAN make you sick. With beef and fish, it mostly depends on the quality/freshness from where you buy it. Eating a raw steak from a grocery store is miles riskier than from a specialty/kosher butcher.
So again, exposure to air is not what determines the risk, initially. Supermarket ground beef isn't even safe to feed your cat (and cats can handle raw chicken, even) because of the low quality and handling, not necessarily because of air exposure. Same goes for steak and fish. The fish found in sushi is expensive for a reason.
In the end, you just have to be smart about where it all comes from.