So your viewpoint is that, if the law on the books criminalizes an enormous number of people who are not really harming anyone, then one should nonetheless support rounding those people up using whatever means necessary?
I mean, I guess your view is consistent and makes some kind of sense. Selective enforcement of the law is a bad thing in many ways, and in an ideal world there would perhaps be no difference between "technically illegal" and an actually enforced crime. Perhaps disastrous policies like rounding up medical marijuana users, longtime undocumented residents, jaywalkers, "sodomites" before Lawrence v. Texas, miscegenators before Loving v Virginia, etc., etc., would "heighten the contradictions" and force civil society to legislate what it actually wanted to punish.
I'm confused how you could be confused by the opposite viewpoint though. The opposite viewpoint is informed by millenia of the reality of law, which is that laws are often not enforced because they don't make sense, and a zealous enforcement of an existing law can be a radical, destructive break with an informal rule. For those of us who see this as simply part of reality, a given proposal to increase or decrease the enforcement of existing laws must be weighed against its practical effects.
The proposal to enforce the immigration laws is controversial because it will cause an enormous amount of suffering, it solves no real problems, it will weaken the US economy, and it is motivated by racial animus and xenophobia.