That would be fair if you could detangle if from specific suspicious behavioral patterns. Like wearing a mask (pre-pandemic) in a neighborhood where robberies by mask-wearing perpetrators are common.

Is it illegal to wear a mask? If the answer is no then the police have no right to stop him for wearing a mask. Police having the leeway to determine what is suspicious vs having to obey the law is what leads to thousands of minorities being stopped, roughed up and arrested for resisting arrest. If you are a minority and do nothing wrong, how many stops for being black would it take before you became a little defensive or frustrated? Imagine your life being constantly interrupted by uniform wearing people with a track record of killing people with your complexion.