When I say “anything” I could be referring to a comment, an interaction, a symbol, or an action. I’m not sure how to explain this without using examples. In hospitals, doctors often identify patients by their disease. This alone is a minor issue but it can be considered indicative of dehumanization.
Same thing with prisons. Being called by a number, being forced to wear the prison uniform, unofficial social hierarchies, solitary confinement, etc. Each one of these things alone is not that bad but they can be considered indicative of dehumanization as well.