I have never committed a crime that lasted for years
How long do the crimes you get away with usually last, and how long after they are committed do they cease to being a crime?
It seems to me that the very crime illegal aliens are committing is their very existence in a political territory that has a different flag than the one they previously existed in. Why should any sensible, humane person have a problem with that? Because there is a law against it? Because if that's all your argument revolves around it's shallower than a puddle.
Open, free, democratic societies consider illegal immigration a mere misdemeanor, 2Parties. Only totalitarian states that value national borders over the right to freedom incarcerate people for that. I strongly urge Westerners who want to see illegal immigration punished with jail time to move to North Korea where they'll live among like-minded people.