While I haven’t heard a direct sermon on modesty from an SSPX priest, the priest emailed all parents regarding the dress of girls period, which has been quite poor. They’ve also published dress codes in the bulletins and mentioned it in sermons. 

In my experience, the people in the SSPX are not too different in certain ways from the rest of the secular world. And many of these are now in the "Resistance" as well. The older priests have given sermons about it, both when in and then out of the SSPX, but many people do not pay attention to the priests soft chidding.

I also think it is mainly the fault of the fathers, it seems to me that some just don't know how to deal with their girls, or tend to spoil them outright. Soft sermons are not going to help either, you have to tell the girl AND the parents that certain things are not acceptable.
  I remember one Sunday we had a certain visiting priest and he got on the subject of what is propper dress. After Mass one of the older girls said "I didn't know short sleeves were a problem?" (I mean the sort of 'half-short sleeve' on some cotton shirts for females). And all I could think to myself was "How could you not know? Did you really not understand what the priest were saying in their sermons over the past X number of years?" As said before, sometimes you just have to be blunt. And I think sometimes this is especially true with some teenagers.

I also think it is mainly the fault of the fathers,

It is not the fathers that teach the girls that their beauty and self esteem comes from getting the attention of boys, it is the mothers that pass this error on. Men always tend to blame themselves and in this case, they are secondarily at fault for not correcting the lie.

It is not the fathers that teach the girls that their beauty and self esteem comes from getting the attention of boys, it is the mothers that pass this error on. Men always tend to blame themselves and in this case, they are secondarily at fault for not correcting the lie.

That may be so, but I have met girls who put importance on what their father thinks/says. Even my own mother was such a girl in her youth. If a father would simply say "You shouldn't do that for X reason", I think it would make a difference. My own father would simply say "Your skirt is too short" and for the most part my sisters don't wear inappropriate things unless it's maybe all they have for the moment - even then it just comes above the knee.
  Maybe other girls are not so... fillial? But I'm certain that amongst those I know, things would be different if the father(s) would just say something.

Education amongst Trads is seriously lacking on all sides.

Last Tradhican wrote: It is not the fathers that teach the girls that their beauty and self esteem comes from getting the attention of boys, it is the mothers that pass this error on. Men always tend to blame themselves and in this case, they are secondarily at fault for not correcting the lie.

That may be so, but I have met girls who put importance on what their father thinks/says. Even my own mother was such a girl in her youth. If a father would simply say "You shouldn't do that for X reason", I think it would make a difference. My own father would simply say "Your skirt is too short" and for the most part my sisters don't wear inappropriate things unless it's maybe all they have for the moment - even then it just comes above the knee.
  Maybe other girls are not so... fillial? But I'm certain that amongst those I know, things would be different if the father(s) would just say something.

Education amongst Trads is seriously lacking on all sides.

I did not excuse the fathers, you are correct 100%. What I stressed is the it is the mothers that TEACH the error, the lie to the girls. The father must correct the mother before the children are old enough to hear. It is a lifelong fight for the father with his wife and daughters, more so with the wife because she is already infected with the decease.  It is up to the father to teach his girls that self esteem and beauty comes from within and not from the reaction of men to them.

The problem is that many people would dress modestly only for Sunday Mass. Then, you see the same people during the week dressed as the rest of the secular world (basically in grossly immodest rags). They are practically indistinguishable. Unless the parents insist heavily on keeping the Traditional Catholic modesty standards at home, this seems to be the norm.

Sermons and dress codes do help, of course; but unless the modesty is practiced and reinforced at home, and since infancy, they will not be sufficient. There needs to be a deep contrast between the standards of the Catholic home, and the worldly fashions, especially nowadays, when society has lost all grip on chastity, decorum, and even reality.  

Bingo!

If the father of the home is not teaching and enforcing the rule, all corrections outside the home will go unheeded... 

And, more importantly, the men of today are slobs... If the father doesn't behave in an exemplary manner, his children will follow his bad examples, regardless of what priests and others may say or demonstrate outside the home.

A priest is not a parent.  It is NOT his job.

I agree with what you wrote except I disagree with this part above, for it is ALSO his job.