One of the most devout Catholics I know wears pants sometimes. Not often, but sometimes. I confess, it fails to shock my delicate sensibilities.
There is utopianism and then there is Catholicism. The two are not always as similar as they appear to us. For instance, I'm against the idea of women being doctors and lawyers, in general, of women in the workplace doing jobs that should be done by men. Not only is it inappropriate, but it has flooded the marketplace and is in part responsible for this employment crisis, since you have people of both sexes searching for work and not just the male bread-winners.
Does this mean I won't use a female doctor or lawyer, or that I'll look down my nose at her as some lesser being? Of course not. That's just the way things are right now.
If you remember me during that whole NFP phase, you know that I'm not just some loose, casual guy. I went through my own utopian phase. But the real Catholic faith does have a certain degree of leeway. I think it's about accepting imperfections, accepting we're in a fallen world.
When it comes to Fifties-ism, the American SSPX really suffers from this excessive concern with dress code. I can think of other things they should be more concerned about.
This is not an SSPX problem, however -- it's an American problem. The French SSPX and French sedes are different. I've seen French SSPX Masses where the people are dressed like slobs. The whole dress-code thing taken to these extremes is, in my opinion, a Puritanical holdover that has crept into the Church. To me there is an element of pride here, and dressing in a way to show off your modesty in an exaggerated way is pride. It seems we Americans always have to set ourselves apart somehow, we have to do something different to feel like we're better than others ( I'm generalizing, of course ). But I believe this is also the source of home-aloneism, Feeneyism, anti-Thuc-ism, etc.
If you are reading this with a jaundiced eye, and want to misrepresent my point, you can retort by saying "Why not wear a bikini to Mass?" But I think it's clear what I'm talking about -- dress is a matter of common sense, it's clear to anyone that wants to know what is appropriate and what is not. If a woman comes into CMRI wearing pants, you can feel people thinking "Hm, this isn't ideal, but it won't kill anyone." When someone walks in wearing some sexy outfit, you can feel everyone bristle. It's obvious when a woman is taking steps to draw attention to her bod, there's no hiding it in that world.