Interesting questions.
1/ I've never been to Auschwitz. But I have been to Dachau, which was the first camp the Nazis used and remained a concentration camp throughout the war. I guess it did alter my perspective as standing where history has happened is always a powerful and emotive thing for me. I've been to the Normandy beaches and seen where Anne Boleyn was beheaded etc. I really do feel the power in such places. That said, WW2 has been a life long interest so I don't think I had to visit a camp to feel that. I will visit Auschwitz one day. I also want to visit Treblinka which as I referenced yesterday is where I think humanity was at its most evil. I'm not sure why I want to visit but I feel like I want to pay respects in some way and as it was such a secret place I feel like visiting empowers the victims somehow?
2/ Yes, although I must say I don't think people should "do Auschwitz" like people also "do the saltmines" or "Do the old town" when they go to Krakow. I think people should read about it first to fully respect it.
3/. I've always appreciated the Nazis were amongst the most evil regimes in history and that this was most on display in the camps.