Yesterday I cited part of a ruling by Rav Moshe Feinstein about a man sitting next to a woman in public transport. Here is another part of this ruling (emphasis mine):
[…] even if it brings about lustful thoughts. He needs to fight against these thoughts by distracting himself and thinking about words of Torah as the Rambam (Issurei Bi’ah 21:19) advises. […] However if he knows that he has a lustful nature and these circumstances will cause him to be sexual aroused – then it is prohibited even if he needs to travel on the buses and subways for his job. But G-d forbid that a person should be that way. This is a result of idleness as it states in Kesubos (49) concerning a woman but it applies also to a man. Consequently he needs to be involved in Torah study and work and not be that way. (Igros Moshe, Even HaEzer 2:14)
We can argue about women’s clothing all day. But for some given man and his standard there will always be women that do not meet it (if only because there are so many opinions). So the responsability for his behaviour is always on the man and he must learn to deal with his thoughts.
Some men claim they cannot. I am not a man, so I cannot tell them how they should feel. But it should be possible for men to control their thoughts in normal, every-day circumstances (e.g., public transport, crowds, shopping, children). Rav Feinstein agrees that not being able to control his thoughts is a) not a desirable state and b) this needs to be changed. Bottom line, this is not a valid argument and men who use it to restrict women should be ashamed of themselves.