They don't tend to tear a car apart for nothing or separate people, out of curiosity you mentioned having items seized care to elaborate. As to your dog that is for your dog's safety, caged and muzzled the dog is not a threat.
I do however suspect the current political tensions have a lot to do with it, too many illegal border crossings from the US to Canada in the last few years. The border services are very concerned about people crossing and then claiming asylum and we don't have the capacity.
Nonetheless, it is a bad way to start a trip and you may face a wee bit of anger directed at you, it is not right but calling us the 51st state and calling our head of government a governor thing has people really pissed off up here.