In situation like these Germany has and will ever have a 'historical problem', due to what happened during the holocaust. When it comes to open or close doors, Germany won´t ever be able to act consequently. That´s the weak point, and the enemy knows that. Now many people came into the country without having been controlled or registered in an appropriate way. Among them terrorists.
Miss Merkel surely decided to run again for the chancellor´s seat (election next year), since she needs to fix the huge problems her open-arms-politics have caused.
Having a well organized border control doesn´t mean to be racist or anti-anybody. It´s time to wake up and react. Or like you perfectly said: 'Enough is enough.'

Stay safe in Munich. It´s my home town :)