Laws that allow malicious compliance are bad laws.
Intentions should not be a factor in evaluating whether laws are good laws or not. GDPR is not a good law. It hasn't even put a dent in the problem, and we are worse off for having it.
Obtaining "consent" via nagwalls and other dark patterns doesn't seem like its actually legal per the GDPR. Rather the enforcement is just so slow moving that it appears that way. So your complaint seems akin to saying that the laws against physical assault are pointless, because you were attacked and the police didn't find your assailant.
GDPR has had a huge cost. If it doesn't yield any benefit because it's not being enforced, then it is a bad law, because it has costs without benefit, unlike the prohibition on physical assault, which is "free".
How is it free? London in Victorian and worse in earlier times was a much less safe place than London now and a lot of the credit goes to having an organized police force that takes action to find and apprehend those who commit assault and battery. That police force cost money to create and costs money continuously to maintain.
I didn't say police are free; I am not referring to enforcement. The assertion (by mindslight) is that GDPR is not adequately enforced anyway, so the comparison you make is somewhat apples to oranges.
It costs society nothing to not punch people (complying with the laws against physical battery). It costs society a lot, however, in real economic terms, to comply with GDPR.
Therefore, if GDPR is not being enforced, it is all cost for little/no benefit.
Intentions should not be a factor in evaluating whether laws are good laws or not. GDPR is not a good law. It hasn't even put a dent in the problem, and we are worse off for having it.