The Bundeswehr was created ten years after the war naturally it was impossible to fill its ranks without former Wehrmacht soldiers. Building an officer corps from scratch is nearly impossible in limited time and will without a doubt result in severe quality loss. Obviously the Wehrmacht history of the respective soldier was a huge part of the consideration and furthermore the connections to the NSDAP. The highest ranking officers of the new Bundeswehr were mostly high ranking Wehrmacht officers. The highest ranks ( Oberst and higher ) were extensivly screened before they were considered. High ranking Waffen SS officers were not eligible. Waffen soldiers were allowed to join the Bundeswehr. Obviously it was a special situation but the cold war made it a neccessity for western bloc to start build up a new German army which would now be an ally and the first state next to the eastern bloc. An example which shows this special situation is that for the old awards you had to order a new one without Swastika since these were now forbidden to wear.