Well I'd agree nobody alive to day has any reason to be ashamed of what other people did centuries ago. But that doesn't imply that we must endorse is, defend colonialism does it? Colonialism has victims usually they suffer violence, death and if we call ourselves Christians then we are hypocrites.
European colonial empires invaded the territory and had a huge negative impact on the people who lived here. It wasn't owned by Europeans that for sure, taking stuff that doesn't belong to you is theft, sinful if one claims to be a Christian they cannot defend such conduct.
Colonizers always make up absurd "arguments" to justify their actions yet would be the first to cry out if another culture colonized them, hypocrisy is never far away when one embraces colonialism or fascism.