People have an emotional need to believe that the law is clear-cut and full of bright lines, because a) it makes it easier to say things like "they deserved it" to anyone who ended up on the wrong side of it and b) because it's scary to think that you can do everything "correctly" and end up in trouble anyway.

They literally don't believe you when you explain that this is false of the law in general, and especially false of immigration law, which is deliberately designed to have tons of ambiguity and discretion in it, to enable selective enforcement and keep guest workers afraid and exploitable in their ambiguous status.

I've been in CLE classes about immigration law with practising lawyers who are shocked and disoriented when a sitting immigration judge explains how that corner of the legal system works. Criminal defense lawyers in particular are taken aback by the discovery that many constitutional/procedural norms they've taken for granted their whole career simply don't apply.