Generally speaking, I don't understand why so many have such a great issue concerning the deportation of illegal immigrants.
Some people on the left, myself included understand that in theory, illegal immigrants should not be here and that if they are, they should be removed.
But just like everything else theoretical, when reality meets theory, things get complicated very quickly.
Many immigrants contribute significantly to a local economy. Many have been here for years and/or decades. Many have kids. Many are folks we actually would want in the country as they are law-abiding, contributing members of society. We've long held as a nation that we're richer culturally, societally, economically, and more by including more diverse folks who want to work hard into our society. Many immigrants do this.
So basically it boils down to, we have millions of illegal immigrants in our country...do we deport them? Do we have them live in fear of deportation if they're contributing, successful members of society? Do we have them fear to contact our law enforcement communities because they're in fear of being deported? Do we want to break up families who have been here for a very long time?
Some may say yes, but most on the left say no...that while they need to be held responsible for breaking the law, we can do that with compassion and have them pay a penalty of some kind and move to the back of the line for legalization/citizenship. Most of us don't find a huge problem with this, nor do we have a problem with focusing on violent immigrant offenders and deporting them, even if they have families in many cases.
We also acknowledge that our immigration system is somewhat flawed. We haven't been keeping up with changing situations throughout the world and we've been rather stagnant, which does a disservice to immigrants who we actually would want to have come in. Worker visas? Refugees? We need to be able to have a realistic and grounded discussion about how to handle them and then actually DO SOMETHING about it. But for many years now, we have had an inability to gain the political will to actually work to resolve this problem...there are those in a certain political group that benefit from this problem lingering on and using it as a wedge for their purposes, which is part of the reason, cyncially imo, that they haven't acted...it's too useful a tool.
But the short answer is that we have a problem with deporting illegal immigrants because it's not just that easy. Illegal immigrants are a class that encompasses a lot of complex people, situations, both family, economically, politically, culturally, legally and for those who say we should just deport them all, I think diving into the issue, and gaining a broader understanding of how the immigrant classes break down would be helpful in seeing a bit more nuance in the situation.