People are people everywhere, but I can assure you entering the US can be a much bigger pain in the azz than Canada when being a foreigner as a general rule. Although I have hit a few azzholes entering Canada when flying into the Toronto Airport.
Maybe they had a kidnapping alert for kids matching your kids description. You never know !
But usually it is pretty lax crossing the Peace Bridge. My nephew works at the Peace Bridge on the Canadian side, post your picture I'll make sure he flags your picture as to always hassle and deny entry ! Just kidding !