Ronald Reagan Would Always Call The Winner of the Superbowl, World Series, NBA Championships, etc.
In fact, presidents host various champions of sporting events, both pro and amateur, at the White House. And no one complains. The only DU complaints that I heard was when Tim Thomas, then-goalie for the champion Boston Bruins, refused to meet with Obama. People complained about him.
How is that any different from what Michelle Obama did last night?