The thief's assistant

Two college students on vacation were walking in through a small town, absorbed in an incomprehensible debate.

"...doubt that the soul operator would commute with the Hamiltonian."
"Why should--hey what's that over there?"

There had been a single figure walking up ahead of them, but now there was a second figure which looked much more threatening. A little old lady, the kind that always gets her purse stolen in comic books, was getting her purse stolen.

"HEY! What are you doing!" The thief looked up, and then ran away with the purse. One student stayed to make sure the lady was okay, while the other one chased after the thief into an alley.

But he ran straight into a big guy who had stepped in his way. "Whoa there. What's the rush?" The college student looked him up and down. He looked quite friendly, not threatening at all despite his size.

"I'm chasing a thief, he stole a woman's purse back there! Come on, help me!" The student tried to go around the big man, but it was a narrow alley, and the guy didn't seem to want him to go past. The student suddenly realized how odd it was that there could be such a narrow alley in such a small town.

"A thief? Here?" The big man looked the college student up and down. He looked like the kind of young adult who was always trying to be a hero, always imagining up dragons to fight. Idealistic. Arrogant. "There are no thieves in Townsville. Townsville is a friendly community."

"But he's right there! Hurry, before we lose him!"

The man turned his head towards the escaping thief. He doesn't react. "There are no thieves in Townsville. Don't you dare insult us."

The student sighed. There was no way he'd catch up anymore, not even to get a good look at him. He started to get a little angry at the big man blocking him. "Well then what do you call that guy who ran away?"

"If that were really a thief, he couldn't be a citizen of Townsville, much less a good citizen. He must be a traveler, much like yourself."
"But that's beside the point! You should at least have let me chase after him, if you weren't willing to help!"
"Why are you getting so angry at me? I am not a thief! How dare you accuse me."
"I'm not accusing you. It's not your fault if there is a thief in Towns--"
"I am a citizen! Citizens of Townsville never steal because they always ask politely first."
"I think you're misunder--wait, what was that?"
"I said that no proper Townsville citizen is a thief. I think you are misunderstanding me."

The student was quite exasperated and disturbed at this point. He was about to give up. "And yet there are still thieves."

"No one here is a--"

The student felt he had heard enough from this guy. "Okay, okay, no one in Townsville is a thief. Could you just direct me to the police already, so I can report this?" The man blocking him, satisfied that he had defended the dignity of his town, directed him to a dusty old building in the furthest corner of town.