You're on the right track, but not quite there.

You're right that rare steak is ok because the outside surface has been cooked killing external contaminants. But the contaminants in chicken can exist throughout the meat, therefore it needs to be brought to temp all the way through.

This misinformation could kill someone. Steak and chicken are not the same and do not have the same heating requirements.

If you sear the outside of steak it will kill most harmful bacteria including salmonella. That is not true of chicken where the salmonella is more likely to be throughout the meat.

Please don't give out dangerous food safety misinformation.

Fish and steak are totally different animals (pun intended) and the way they are handled after slaughter is completely different.

Chickens are dunked in a cold bath with a lot of other chickens after slaughter. This creates a lot of opportunity for cross contamination. Air chilling the chicken mitigates, but doesn't completely eliminate, this. It's still very risky to eat air chilled chicken undercooked because the structure of the meat still allows salmonella to more easily penetrate the muscle. Air chilling chicken at scale is a newer approach because it's always been cheaper to water chill it. Air chilled chicken is significantly more expensive to purchase.

Cattle are air chilled, but before they go in to be chilled, the carcass is gutted and washed out. Care is taken to ensure tainted meat is not present during the chilling phase. Chilling cattle is also an aging process that takes several days. You wouldn't eat a raw steak because pathogens do get on the surface of the meat and do have a hard time penetrating the muscle. So yeah, you sear or grill the outside to kill those pathogens. They certainly can get into the muscle so eating a steak at under 165°F does still carry risk of foodborne illness. Still, it's generally safe to do so.

The same can even be said of whole pork cuts. The USDA recommends at least 145°F with a 3 minute rest period.

As for fish, I don't know enough to assert anything, but I'll speculate that it's because fish is handled and chilled over ice very quickly and you're always eating whole cuts. Still, raw fish is risky and it's significantly safer to at least cook the outside.