“Is it tzniut to be standing outside a girls school looking at 8 year old girls?”
Looking at 8 year old girls opens another can of worms. Looking at their mothers is bad enough.
It should be pointed out that the Chashmonaim killed those who brought “karbanos” to the greek gods, not women who may have dressed in a manner THEY do not deem proper but other legitimate poskim did. The men of Beis Shammai did not go around spitting at the women of Beis Hillel who wore things outside on shabbos that Beis Shammai felt was not a tachshit.
Not all poskim state that stocking must be whatever denier thick with seems up the back, or hold that sheitels are not valid hair covering, or that the shok is the entire area from the bottom of the knee to the ankle and so on. What this really boils down to is they have their minhagim and poskim and heaven help anyone who lives their life according to any other poskim and minhagim.