It's probably a mistake to come in and think that anyone's going to change their mind on this subject, but here are a few thoughts based on the States:
1) the term 'illegal' immigrant is a strange one -- many things are illegal, but we don't label the person doing them with that adjective. A driver with an expired license isn't an 'illegal' driver, a student who cheats on a test isn't an 'illegal' student, someone downloading a movie isn't an 'illegal' computer user.
2) I bet that just like in the U.S., a Canadian immigration violation is a civil penalty, not a criminal (or jailable) offense.
3) Everyone chooses what laws to follow -- I've broken many laws in my life and so has everyone who commented on this thread. It's commonly accepted that this does not make all of us criminals, we look at the effect of breaking the law. If someone stays here illegally and welds pipe in Fort McMurray and sends cash home to Thailand, frankly, I don't care. If that gets you all bothered, then you should advocate steep penalties for the people who employ them -- no one respects a system where the big lawbreaker gets off scott-free while the little guy gets crushed.
4) I totally agree with what Steerpike wrote above -- the idea that someone can move around the world freely or with great difficulty based on the chance of where they were born is a very difficult one for me to accept. This thing that we call 'illegal' immigration used to be called 'immigration'. The world is not a playground for first-worlders, people from everywhere have a right to travel and better themselves. Sometimes they have no choice but to do it against regulations -- I've known many people who did that, and many times they paid heavily for this, and the companies, people, and countries that let them be exploited paid nothing.