TBH I see no real problem with buying and reading a book about the Waffen-SS whatsoever, and I don't think anybody should be dragged over hot coals for doing so. WWII was a nasty affair and learning about the nasty bits can be argued to give a better and more complete understanding of the conflict.
Saying that I have no urge to buy a book about them myself, I've read enough about WWII that I have a pretty good understand of just what a great bunch of shits they were. One of my great uncles saw the aftermath of their handiwork with civilians in Italy and after that his unit didn't give them much benefit of the doubt when they came into contact with them.
The only problem I see is glorifying them or revisionism to try and downplay what they did. There was none of that here so no harm done and nothing wrong with showing and sharing what new books you've picked up.
But back to the SAS title, how's that illustration with the white beret eh?
I can't believe anyone here hasn't said a peep about the early tan beret going for £22,000. Might just be me interested in Commonwealth land forces militaria though!