Is it true that there's no risk of parasites from sushi/sashimi from North America?

It is incorrect to assume there is no risk. Any food whether it's cooked or not there is still risk of getting parasites even cross contamination from reputable sushi joints example through carelessness etc'

It is true that the FDA requires all fish/seafood to be frozen, if it is intended to be consumed raw as in eg. sushi and sashimi.

I don't believe this is a 100% waterproof system, however, because a) freezing does not necessarily kill all parasites and pathogens, and b) in any case it is difficult to enforce this regulation, and some never-frozen product will no doubt get through.

This is to say nothing of the fact that for best results (gastronomically speaking, that is, ie. in terms of flavour and texture) you should really eat the fish at its freshest and without it being frozen.

Any raw food has those risks

Any food consumed in its raw state poses some risk of parasites. you can not eliminate the risk completely without thorough cooking. But it is less risk in the U.S.A. than in other places. My advice is know your sushi man and his reputation, and don't get sushi from a Chinese buffet where it sits on a table all day either.

Try eating as many as you can to find out.

There is no requirement that it be frozen. Most though generally is, but fresh is MUCH better!

The "better" sushi joints even buy LIVE fish. You eat their sashimi and you are eating something that was alive only minutes before!

Here is the BEST place I know to buy your own sushi items; http://www.catalinaop.com/

Notice you can also buy some LIVE stuff there!