What should the world have done?
Sat back and let Putin take Ukraine, then the Baltic states, Finland, Poland, Czech republic? How far would you have let him go before thinking that maybe the EU might need to stop him?
Do you really believe Putin would have stopped at the border with Poland?
Who would you suggest could have supported the Ukraine in their fight?
The US has done some very dodgy shit...we know this. They are also the only other superpower prepared to "fight for democracy" even if that democracy is flawed and imperfect. It still beats the shit lives that many Russians lead unable to voice opinions or vote out a homidicidal maniacal leader.