I certainly wasn't raised in an atmosphere of externally imposed modesty - we all would strip down to panties and swim in a lake or river when we happened upon one unplanned - but my childhood friends and extended family members all reached a point in adolescence where we naturally became more conscious of our bodies, and our comfort levels in "exposure" changed. The (I guess in liberal, 1970s circles) "she's going through a 'modest' phase" <eyeroll, wink> period.
I dress much the way Jenna described as what she feels is modest for her. The difference - and I think it's the essence of the whole irritation with the modesty threads - is that "modesty" never, ever crosses my mind. Never. Colors, fabrics, fit, and context all come into play, but never whether my clothing would be considered modest or not.
I once had a vagrant aggressively stop me on the street in front of a theater to tell me I have nice toes. I was wearing an above the knee, spaghetti strap dress at the time. Not once did it make me reconsider wearing strappy sandals. I've had men leer at me in a fire department uniform, which is not the most figure flattering attire and certainly keeps everything tucked and covered.
There was also a vagrant who would stand on the median on NY Ave and scream complete gibberish at people while they sat in traffic, leaning into your car if you had the window or top down. I'm pretty sure he wasn't undressing any of us with his eyes, just crazy.
Odd people do odd things. I try not to read into what I think their foundational motivations are.
I find the threads irksome because of their sentiment: I need a bathing suit, but no, not THOSE standard, appropriate for active beach fun ones because I am not a ho like the rest of the world. Or: *I* am so far above those of you who obviously are seeking attention in your suits, I will be wearing a full-on track suit to our pool party. Because, you know what? Bathing suits are culturally appropriate at the beach and poolside, and there is a very wide range of suits that prevent spillage and mask "flaws" even.
You are most definitely attracting attention in your track suit, and you know it. The difference is that you are drawing attention to your righteousness. Self-righteous isn't flattering (or modest) on anyone.