Unlike many years, the USA management decided to bring a "team" instead of the best individuals. Everyone has a role and for a guy like Ryan, who is only a one way player, the USA management felt he wasn't better offensively than Kane or Kessel which is a fact. Nor, does he boast the two way game that Callahan does.
Is he better than Oshie? Sure offensively, but I don't think all around he is, and Oshie is going to play a 4th line role. He also cannot play center, which is why Stepan is rated higher than him.
On D, most if not all are solid two way defenders outside of maybe Shattenkirk. In the article the management team was not happy with Yandles defensive ability and with so many of the D selected able to move the puck already, is it worth it to bring Yandle with that defensive deficiency? Also have to remember that Pavelski is going to probably play the point on the 1st PP unit with Suter. In a tournament this short, you can't waste a spot on the scratched list for a one dimensional D man.