That really depends on the magnitude of the two problems. "Don't throw the baby out with the bathwater," "The cure is worse than the disease," etc.
However, at least from my perspective, the harm caused by allowing employers to continue to abuse the information asymmetry is significant and real, while the idea that keeping people in the dark makes it somehow more likely that good employers will reward good employees seems to have no rational basis in fact. (It is, I believe, much more likely that good employers will reward good employees regardless of whether they are required to disclose employee compensation.)
Thus, unless you wish to claim an ideological argument of some sort (which I would say should always be superseded by evidence of actual harm to actual people on the other side), the only remaining argument I've personally seen against pay transparency always appears to boil down to "I assume I must be paid better than the people around me, because of my obviously better skills at $JOB and/or negotiation, and I'm afraid that if everyone knew they would be jealous of me."
This is absolutely true.
However, in practice, while there are certainly workplaces where differences in pay are primarily due to differences in actual productive output and value to the team/company, there are also many, many workplaces where the differences in pay are entirely due to either better negotiation skills (which have absolutely nothing to do with the work in question), or how much the people deciding on the pay like the workers in question....including how much the workers in question toe the party line and are willing to sacrifice and abuse themselves for the sake of the company.
In a case like this, what is responsible is to acknowledge the good-faith cases, and put rules in place (like pay transparency) to help fight against the bad-faith and abusive cases. "We should allow companies the freedom to continue to abuse their employees, because some companies instead use that freedom to reward good employees" is not a particularly compelling argument, at least to me.