Colonialism of the past isn't very relevant in considering the actions of another geopolitical power now...western societies will see Chinese aggression as acts of aggression exactly because we've moved past that mindset. Cultural and societal norms have changed the way we think about colonialism. China's "relatively tame assertion of a territorial sphere of influence" hinges on comparing two distinctly different time periods which makes little to no sense. By that metric, the abuse of workers in China and the deplorable standards enacted are relatively tame when compared to say...slavery.
China doesn't get a pass based on how brazen their actions are. Actions will be actions.