That's no Liberal Mantra, that's a strawman you're erected. But since you bring it up... I'll bet most of them are law-abiding, other than having snuck in. I expect most simply want to make a living and avoid attention of the armed gov't agents, kind of like most of us. What do you think?
YT3 - You are correct in stating; "I'll bet most of them
are law-abiding, other than having snuck in." But you ignore the fact that they committed a crime by having snuck into this country. There
is a legal process to being a legal immigrant.
What if a person snuck into your house (the country) to live, but other wise was law abiding, would you condone it? If he paid rent, and was a legal tenant (immigrant), I'm sure it would be different. I know the analogy is not exact, but the reasoning is close.