Castiel could feel the man's anxiety at being approached, but he did nothing to back off or ease his discomfort. He still wanted to see the reaction to it.
"You're blind," he said bluntly. He wouldn't go so far as to probe the man's mind or soul without provocation, but he wouldn't conceal what he already knew to be out of place. "And you're dressed... oddly. You can't deny that warrants at least some explanation."
It might have been an angel's arrogance; demanding explanation when his own presence was counter to that of the mortal realm. He knew what he was. The question was what this man was.