Its not the same thing at all.
One, the german thing was government mandated, the NFL is the business owners decision.
Two, the team was banned for a year in Germany, the nfl team would be fined.
Three, they dont even have to stand, they can stay in the lockerroom if they dont want to stand.
Also, the NBA has a policy that requires people to stand, but of course the NFL is the bad guy.
NBA's rule: (2) Players, coaches and trainers are to stand and line up in a dignified posture along the sidelines or on the foul line during the playing of the National Anthem.