I think these bozos (no insult to clowns intended) are doing a bit of "proactive" policing.
This come from one of three sources.
1) FNG wants to make the big bust and questions everybody about everything. Where are you going? Where have you been? Why do you have on brown shoes? Why are you driving while black? Sooner or later someone calls and complains about harassment.
2) Badge Happy jerks. Dealling with one is bad but a pack of them are like high school bullies. They need to be shown the door.
3) Some manager says you must conduct 5 interviews a day, 7 traffic stops a shift, have 10 contacts per fortnight. The manager needs numbers for a weeky spreadsheet or he/she will not get a good review form their boss. In this case the LEO's go through the motions as quickly as possible and are generally demoralized by the whole affair.
The young gentleman did the right thing. Polite but firm. He was more proffesional than the TSA dweebs and LEO.
If you don't mind missing your plane, try these helpful hints.
Ask who to contact at Internal Affairs or Profesional Standards to file a complaint. That just let's them know they are in for the same treatment from their own team. Never a fun time.

Decline to go down town. Make them arrest you. If they don't have anything to charge you with they will huff and puff but let you go.
If they charge you with hindering, sue the pants off of the agency.