That’s disgusting. Has it ever occurred to you that more than one party can be responsible? One person has a responsibility to keep his mind away from sin, and the other has the responsibility to not place obstacles in front of her brother in faith. It is easier to govern the flesh when others are dressed modestly, than when others expose their bodies. Thus, one should try to dress modestly.
Soldier of Mary, hopefully you didn’t intent to use such harsh words, as “disgusting”. Someone’s opinions and beliefs, when not in opposition with Catholic teaching should be treated with respect - which seemed lacking in this response.
To the point in question, it is true that if a man were to lust after a woman on the street wearing nothing but her unmentionables - both are likely culpable of sin. But, they are culpable of different sins, and likely to varying degrees.
The viewer has the opportunity/choice that when seeing the unclothed beauty of God’s creation to turn his eyes and think of more holy things. If he fails in this, he is culpable of lust. However, another man could view her at the same time, and not fail, successfully ignoring the spectacle, and lovingly returning attention to his wife. So the sin of lust/unholy thoughts does lie in the viewer, as two people can be in the same situation, yet react differently. Therefore, the woman’s action is not complicit in the sin, as she did not cause the sin, she merely caused a situation where it was possible. In the same way a banker isn’t responsible for bank robbery by opening a bank.
Now, the woman whose intentional “wardrobe malfunction” has not made the best choice either. Her situation and choice in dress did allow a man to fall into sin. But, she is not culpable for his sin. She is culpable for lacking modesty, and dressing in such a way that lacks charity by not being concerned with how others will be tempted. She should have considered her brethren’s eternal souls when she left the house, and for that she is responsible. But, let’s imagine this same woman is underclothed because she has just escaped an attempt to rape her, and is therefore unclothed. I would find it hard to believe any priest would find any culpability for her in that situation. Yet, someone unaware of the situation could still fall into lust at the sight of her.
Modesty is essential, as the Cathecism notes. But, we should not assume that one’s sin in lacking modesty also implicates him or her in another’s sin of lust. While they are related, each has sinned in different way - they don’t share that sin.
Catholics do have a responsibility for dressing modestly. However, this is, and always will be a matter of prudence, as the Church would be unwise to use Her Magisterium to dictate codes of dress.