Imperialism was the norm, but hanging children for stealing bread was also once the norm. That doesn't make it right.
It is interesting that while a country would march its troops into somebody else's territory, subjugate the people and steal their sh!t, back at home there were strict laws and penalties against theft.
And in the case of 'Christian' countries, just where did Christ give the OK for it?
I am inclined to agree with the second part of what you wrote. I have German pals who feel they have no need to apologise to me for the third reich and I in turn feel I have no right to demand any such apology. What happened was nothing to do with us.