Why does Anova sous vide tell me to cook salmon to unsafe temperatures
A fair amount of cooks and recipes disagree with the official guidelines when it comes to salmon's desired cooking temperature. The 145F guideline applies to all fish and shellfish, and is meant as a safety standard, not a culinary guideline. I've seen target temperatures for salmon ranging from 120 to 150F (most being in the 120-135F range).

The main reason for the 145F temperature is parasites such as Anisakis, which requires the following to kill:


  How can I prevent anisakiasis?
  
  Do not eat raw or undercooked fish or squid.
  
  The FDA recommends the following for seafood preparation or storage to
  kill parasites.
  
  Cooking (Seafood in General)
  
  
  Cook seafood adequately (to an internal temperature of at least 145° F
  [~63° C]).
  
  
  Freezing (Fish)
  
  
  At -4°F (-20°C) or below for 7 days (total time), or
  At -31°F (-35°C) or below until solid, and storing at -31°F (-35°C) or
  below for 15 hours, or
  At -31°F (-35°C) or below until solid and storing at -4°F (-20°C) or
  below for 24 hours.
  


You should research what other parasites and bacteria may be found in the salmon you source, and what mitigation strategies there are (such as freezing, as seen above). If all of them can be done without heating the fish above 120F, you may have a way to follow those guidelines safely. Otherwise, stick to what the USDA, FDA, and CDC agree on :)