Was the homeless man wrongfully/illegally arrested?

My uncle lives in an expensive neighborhood. The only people you see on his neighborhood is the people that live there, nobody else passes by. It's also waterfront property about half a mile from the nearest stores area. Yesterday there was this homeless guy just walking by the neighborhood and doing nothing illegal, just walking by the mansions outside their property. The neighborhood is not private with any security gates in order to get into it.The neighorhood cops watch car just happened to be driving by and the homeless man gets arrested just for walking in that neigbhorhood and 2 cops tackle him to the ground as soon as they get out of the car he gets put in the car and driven away. Do you think the cops had a suspicion that he'd try to rob a house or maybe it's illegal for certain poor people to walk by rich people's houses or was that just wrong and should the cops have just let him keep walking?