“Since when does tznius mean deliberately wearing out-of-style clothing? Actually, wouldn’t it make more sense to keep up with trends, so that we’d blend in more with everyone else? “
I actually think this makes sense. IF the real purpose of tzniusdig dress is to not call attention to ourselves, then how can the garb of certain Jews ever be considered to be tziusdig just by virtue of it covering the whole body. If people are staring wherever they go, how is that any more modest an attire? I think tznius should reflect trends but without going overboard in our mode of dress. We can be both stylish AND modest.