It's been happening forever. Forgive me if some of the following is not historically perfect, my memory/interest isn't always up to this, but:
The English spent years trying to emulate porcelain; they painted blue chinese?/japanese? scenes on their wares; they copied delftware; and that's just the pottery stuff. No doubt that every culture has been affected by every neighbouring one, or the one they invaded/were invaded by.
Ad infinitum.
Should we now be upset by this? Possibly, probably. Can we change history? Should we continue to steal everyone else's ideas? Probably not. Will we?
I agree with Liam, "if your intent is exploitation, bad. If your intent is to create beautiful things, how can it be wrong"