Loitering in his car at a park? Hahahahahahahahahahahahaha
Cop was inquiring into his purpose in being there under the suspicion of loitering (hanging out somewhere for an illegal purpose). He could have remained calm and non-threatening, and simply stated his purpose. Like it or not, most crimes are committed by people matching his description, and cops are naturally more likely to inquire about purpose when they come across someone of his description apparently loitering. It would be stupid for cops to ignore the overwhelming odds that someone of his description, in circumstances like when they came upon him, was engaged in an illegal activity of one sort or another. They are allowed to inquire. How people react to that lawful inquiry can often get them in trouble.
Huh.. who knew, you support a communist police state..
Like it or not, he wasnt loitering. Like it or not he should be presumed innocent until he proves otherwise. Like it or not, police arent here to investigate based on their suspicion, they are here to serve and protect everyone.
You just proved your true ignorance of our rights.