How would you write a law that accomplishes your goal?
Where [..] is a rough definition of dark patterns which there exist multiple of in CS and which you can base on factors like 1) deceptiveness, 2) intend to manipulate the users behavior, 3) how it interact with various human feedback systems etc.
The thing about law people on HN often tend to forget or complain about is that they intentionally do not need to be perfect precise scientific definitions, predicate logic, or anything like that. This means you can reasonable describe them by likely effect and weather it seems reasonable that the effect could have been intended (without bothering to actually determine intend) without needing to go into _any_ technical details outside of clearing that indeed any form of user interface is covered.