You don't have to be omniscient to realize an action might have a consequence that wasn't intended. I don't go 100MPH on city roads because I don't have to be omniscient to realize I might end up killing someone even if I don't intend to.
So OF COURSE regulators should consider ways in which their reulations might cause unintended harm. This is a major reason why US Federal regulators almost all have mandatory public comment periods -- third parties might be able to point out some of these unintended consequences. Regulators might not always make the right decision, but they should at least be making informed decisions.
The attitude should be "We considered that possible outcome and the benefits outweigh the harms (or not)", rather than GP's "well that shitty outcome sucks, but guess what? Not my problem".
I honestly cannot believe the idea that regulators should be considering both positive intended and negative unintended consequences of regulations is controversial.