This isn't unreasonable if you can show me that pathogens transmitted in this fashion are a serious concern.
How often do people get diseases from raw fish: does it happen to 1 out of every 10 customers? Or 1 out of every 10 million? Probably somewhere in between, and at some point we'd draw the line and say "Your taste preferences are not worth the disease this causes."
Most restaurants would voluntarily freeze their fish if there wasn't a law anyways. No restaurant wants the stigma of food poisoning hanging over their heads.
All the bacteria is killed off when the surface of the meat is grilled. Now if they wanted to put a raw steak on your table for you to eat, I think the FDA would have a problem with that.
We have a high population of Ethiopian in DC with a lot of restaurants. Some of items on the menus contain raw meats. I don't believe it's cooked in anyway.