I think Colonialism is more of a neologism for 'imperialism' since the US empire has a pretty different form from the old European empires. In US Parlance it seems to refer to a wealth pump moving resources from the undernourished colonies to a corpulent administrative center. Cultural artefacts could be an example, though of course this doesn't refer to physical artefacts that the original owners lose. It's a bit weird to me as well, though I can see how stealing a cultural artefact to put in a museum and copying a hairstyle could feel similar to someone living with inherited trauma.