There is a German band named "Oomph!" who influenced Rammstein very heavily. You might want to check them out.
Only Paul does, and he didn't get them until kind of recently, I suspect sometime over Rammstein's hiatus after Rosenrot, since he didn't have them over the Ahoi/Reise Reise tour.
Rammstein ist ein rockgruppe von Deutschland. Translation: Rammstein is a rock group from Germany.
In American society yes, but if you really like the band for it's meanings and lyrics than no. If you are German though, it's completely normal, seeing as Rammstein is only classic rock.