How does bacterial contamination grow on food, and is the standard advice to cook your food to a high internal temperature wrong?

The standard advice, for both steak and fish is to cook them to an internal temperature of 160 degrees to kill any bacterial contamination. Is this overly simplistic advice that's mostly incorrect? Please hear me out:

In the case of fish, the pathogen people worry about is listeria and it's generally introduced by incorrect handling at the fish processing plant. For beef, we're talking salmonella and friends. Same situation though: "The muscles of healthy animals contain less or nil microorganisms though, meat can be contaminated during slaughtering and transportation " (see article). To me it seems that the bacterial contamination is therefore on the surface of the meat or fish.

When we put meat or fish into an oven or on the grill, the outer surface is cooked first, eventually heating up the inside of the meat. By the time the inside of the fish or meat reaches medium-rare or medium, the outside has long surpassed the temperature needed to kill any pathogens on the surface of the meat. If we know that the pathogens are introduced on the surface of the meat and are killed off when we heat the surface, why is the standard advice to cook the fish and meat to an internal temperature that's unnecessary and potentially makes the protein taste worse than it needs to be? Do the bacteria grow into the meat or fish in some way? I imagine that they way they grow is along the surface of the meat, so unless you're cooking hamburger, there's no reason in the world to overcook it. Am i missing something?

I've been thinking about this question of food safety for a while, and I was hoping someone knows enough about this topic to illuminate the situation.