"Why you should avoid raw salmon"
"Raw salmon dishes—tartare, crudo, sushi, marinated and cured salmon—are growing in popularity. But unless that fish has been frozen first, it would be wise to pass.
"That’s because a tiny tapeworm larva may lurk in the raw salmon flesh, just waiting for you to eat it so that it can take up residence in your digestive tract. ..."--John Rowley
That's a reasonable warning for consumers preparing such items at home, but shouldn't be a concern for eating in restaurants. The FDA requires that sushi fish (except for tuna) be frozen to kill parasites:
" In the U.S. parasite destruction is required for those species where that hazard is identified"
Only tuna can be served without first going through the freezing process.
I'm skeptical that most chefs (other than trained sushi chefs) who serve raw salmon are aware of that law.
As it says on the page you linked to, "most chefs will claim that they use 'fresh' salmon ... This may be because they do not know, perhaps it is delivered thawed by the local supplier (who may or may not have frozen it according to the requirements), or they may even use fresh, never frozen, salmon."
This is a complex subject, from people that exaggerate to those ignore or dismiss the risks. Here's an article from a very knowledgeable guy closer to the latter:
The FDA requires that fish sold to served raw be frozen to *very* low temps, except for tuna which has a negligible parasite risk. But enforcement is left up to local officials. Also, even fish sold to be cooked is often served rare or at least not cooked enough to kill all parasites. And tuna is flash frozen at sea because of the time deep water ships take to get back.
The risk of getting parasites from raw ocean fish is real and rises with fish that are closer to the shore. Salmon, living part of it's life in freshwater, is even higher. But so is dying in a fiery car crash on the way to a restaurant, movie, etc. The reported incidences of parasites is extremely low, although of course there are likely unreported incidences.
Our digestive systems are very good at eliminating parasites, but certainly not perfect as the parasites have evolved with resistances.
My personal approach? I have a *very* cold deep freezer -- cold enough to preserve the texture as well as kill the parasites. (It has to get very cold, otherwise the parasites just go into hibernation.) So I freeze all the fish (except tuna) that I use at home, even those I intend to cook. At the sushi bar I take the risk - after all, I drove there!