Many organization and companies have what is called a morals clause. When a company or organization hires or sponsors someone that will be in the public eye representing them, they often make conditions to the contract to prevent the person from embarrassing them. This includes things that would otherwise be legal. From the article, it sounds like this is just one of many times she has violated the terms of her contract and that was the last straw.
I do agree that poor sportsmanship should be cause for suspension, especially when you are an Olympic athlete representing an entire country. Any athlete is a representation of their team, their organization, or in the case of the Olympics, their country. They are not acting only as an individual. They have responsibilities to treat others with respect, display good sportsmanship, and carry themselves with dignity. If they are not able to do this, I think suspension is a fitting consequence for poor actions.
Bad sportsmanship is one of the completely valid reasons to get suspended. While you're on a team, you're acting as a representative of that team. When you act out and spout off, that reflects badly on the team, and the team is clearly able to punish you. Hopefully Hope learns her lesson and starts acting a little more professional.
I believe Hope Solo was treated unfairly in this situation. The United States encourages free speech, or at least, tolerates it. Olympic athletes seem to be expected to be role models. She is human and she is from a country where free speech prevails. Allow her to be herself. There are professional athletes who are arrested for violent crimes, and I believe they return to their teams. Why the double standard? Is it because she's a woman or is it because she's not a professional? Either way, her punishment seems excessive.
Hope Solo should not have been suspended. While her comments could be perceived as poor sportsmanship, it was said after a tough loss in the Olympics in the heat of the moment. Suspending her is an egregious penalty and should be reserved for a severe offense such as taking drugs.