“We do object to women wearing clothing which does not meet the minimum standard of halacha.
We cannot stop people on the street from doing so, but we do still find it objectionable.
And if we were in charge, we would stop them.”
i think p_b_a summed it up succinctly with that comment. if we could stop them from wearing it on the street, we would. but we dont have to get ourselves a multi-year prison term to do what is right. here the boys at most risked probably a fine and maybe probation. and they knew the chances of them getting caught in the first place was pretty close to zero. so they did what is right.