OOMIS — I’m very confused reading your posts. You talk about girls/women who are not keeping the halachos of tznius (shorts and sleeveless shirts are assur al pi halacha according to EVERY Orthodox opinion), and then say they are still tziusdik because they don’t speak L”H, do Chessed, etc. What does that have to do with it? We are not discussing if these people were frum — we are talking about a specific set of Halacha which they were not keeping properly. Just because a person is careful with some Halachos doesn’t change the fact that they may not be keeping other Halachos, and certainly doesn’t change the definition of Tznius. Yes tznius in a general sense can include avoiding loud and showy behavior, but there are specific Halachic (not Hashkafic, as you imply) parameters that ARE black and white. Can a women still be “tzniusdik inside” if she is not keeping these Halachos? Perhaps, but that doesn’t define her a an “isha tznua” any more than someone keeping part of the halachos of Kashrus can be called “keeping kosher”.
I agree that even when someone keeps all the dinim exactly, they may still not be in keeping with the spirit of tznius, but that simply means they are also not completely tzniusdik — it doesn’t mean the halachos don’t count!
It is true that there are differences of opinion with regard to certain aspects of tznius, but certain aspects are universally accepted. Some things are clear chumras: those who wear seamed stockings and double head coverings are following their poskim, who have various reasons including tznius, kabbalistic concepts, etc., but even they do not say one is violating the ikkur din of tznius by not dressing like that.
Then there are certain guidelines where poskim disagree, some saying these aspects are an integral part of tznius, and others disagreeing (such as the part of the leg between the ankle and the knee with regard to socks).
But certain things are unarguably required al pi halach — such as wearing pants, bathing suits in a public place, and a married women covering her hair. There may be slight differences about details (the famous “2 tefach” question, or the psak from Rav Soloveichik that a man does not need to divorce his wife over this issue) but one would have to say that if your mother did not cover her hair, no matter the time period, she was not keeping the halachos of tznius al pi din torah. This is not to say she was a terrible person, or any less “frum” in other areas. She may have been much more “frum” in many other ways, and may have kept many other halachos much more carefully then we do today. But Halacha is still halacha!!!!
As you mention, during a time period when it was very difficult to remain frum, it is impossible to judge their behavior. This was compounded by the fact that many people had less knowledge of Halacha as unfortunately the Jewish education system in the US left much to be desired. Those who remained at all frum are deserving of our admiration. However, things that were wrong are still wrong — do you have any evidence that even the poskim of that time “allowed” these things? It seems more likely that most Jews simply knew less about the details of Halacha — not as you say “A lot of things were done in those days that rabbonim do not accept today, i.e. using baby carriages in a place where there is no eruv” implying that the rabbonim in those days did accept it.