AcidETCH,
You're right, the Canadian dental school interviewees don' t get taken for a lunch by D-2 students as some US schools do. But I think you'd be generalizing too much to say that students don't get treated well here in Canada. True, I'd bet big tuition schools like NYU, Tufts, BU, UPENN, and U of Pacific SHOULD be treating students to lunches and organized tours---it's the least that they should do to entice you to pay their tuition. I think Canadian schools don't roll out the red carpet to interviewees simply because they are very selective and don't need to win over their applicants. But once, you're in the faculty you're treated with respect and fairness.
With regards to the interview process, the reason why interviewers don't ask you personal questions about your motivation to enter dentistry is that all Canadian schools have recently (2-3 years ago) switched over to a standardized set of "situation-based " questions. They found that too many students knew beforehand what questions they were going to asked and so had prepared answers for them. Classic ones are "Why do you want to be a dentist" and "What would you do if you saw a fellow dentist performing poor dentistry"? These new questions place you in situations that you've probably never found yourself in before and you have to draw from whatever life experiences you do have to answer the qustions in a appropriate manner. Do these interviews allow you to talk about how many hours you've shadowed a dentist or your research experience? No, but it does show how you can think on your feet (judgement), your ability to adapt to unique situations, and your level of maturity.
Hope that this helped to clear some things up. You may have perceived that you weren't treated well--but I know the interviewers respected the fact that you made it to the interview phase of the competitive selection process in Canada.