For everyones info, single male travelling alone is no 1 on their list. Race/ethnic background is "largely" irrelevant. This is because they are scared if they racially profile, terrorist groups will find people that don't fit the profile to do their deeds.
I know this because I used to get dragged in all the time as well. I had one immigration officer who was quite chatty (And he was reading Ontario outdoors) and I simply asked why I was being pulled in all the time. Answer: Single male travelling alone.
I'm sorry you had to go through it, I can totally relate, but if I moan about it, it won't change. Your approach works the best, suck it up and smile. :whistling: