Why were people besides the Jews were put into concentration camps?

They were either considered to be political enemies or they were considered to be inferior. Either they were considered to have a racial influence not supporting the aryan race... i.e. eastern europeans (russia, serbia, etc.), gipsy... and considered as dangerous influence like handicapped people and gay people having negative influence... this means they were persecuted due to their family heritance or behavior... or they were opponents not supporting his "leader and rescuer" idea, i.e. communists or rigorous christian groups not accepting the "new saviour" replacing Jesus.