Next time try taking a seat in the back without going inside and let me know how that goes.

At CYYZ, my record is 25 minutes from the time I got off the plane, got on the shuttle bus to customs, went through Canadian customs, stopped by the ticket counter, went through American Customs, went thru security, rode on the shuttle bus back to our concourse just in time to hear "final boarding call" for our flight.

It's not the ticket agents that make the rule, so instead of wasting the time arguing with them, just hurry through customs and get back to the plane. We work in the airline industry, get used to running through airports and doing things that don't make sense.