I actually recall this story of a group of missionaries who went to Papua New Guinea. There the people that are in the primitive tribe wear very little clothing. The men wear penis sheaths and some jewelry and the women wear grass skirts and some jewelry. That is it.
The missionaries were trying to get them to be more modest and gave them t-shirts. All the tribes people wore their t-shirts with pride. Then a storm hit (it rains very often here) and all of their t-shirts got wet. A whole bunch of the tribes people sat in their wet shirts and many got pneumonia and a few even died. When they went without t-shirts their skin dried way faster and they didn’t stay soaked for long periods of time. I would say that although the missionaries were trying to do good, they ended up making a very large error that costed lives. I think in tribes it is not fine to modestly go around without a top, but obviously practical when you live in small houses up in the trees without places to store extra clothing.
Modesty does depend on culture. In the Victorian era it was immodest and scandalous for a woman to show her ankles. Today that is obviously not true. No matter what time it is there will always be lust around. There was in the Victorian era when women were covered from their necks to their wrists to their feet. In tribes people walk around topless all the time because that is just the cultural garb. Everyone’s breasts are showing, so no one gives it a second thought. It is not immodest.
Now in our society I think it is perfectly fine to wear things that hit a little above the knee (within a few inches or so depending on leg length) and wearing tank tops or shirts is fine as long as they aren’t low cut and are worn in the appropriate setting. Like not wearing a tank top , shorts, and flip flops to church.
If you have such bad lust problems that seeing shoulders or knees, then you probably need to get help through counseling. You can’t spend all your time blaming women, because even if all women were dressed in Victorian style clothing (which is hot and uncomfortable especially in 100 degree + weather) you may still have problems with lust. Men did in the Victorian era and women were totally covered back then.
There is a reasonable level of modesty we should all dress in to help protect those struggling with lust, but when we start having double standards or asking people to sweat to death, we go too far. We need to not pass off our sins onto other people like Adam did in the Garden (the woman made me do it!), but instead teach our children to take responsibility for their own actions and short-comings. When they see us blaming our sins on everyone but ourselves, they will not learn personal responsibility.