In everyday life, people either use it to either justify actually existing colonialism (Assyrians conquering the Levant justifies Israel stealing land from Palestinians because that's what people in that region of the world has always done) or to diminish victims of actually existing colonization (the Qing dynasty commited genocide against the Dzungar Khanate so we shouldn't feel bad when the Japanese empire commited genocide against Chinese people). Occasionally, both would be used at the same time (the Aztecs had a brutal empire, so they shouldn't bitch about getting owned by the Spanish).