If you're a dude or a bro, before you down-vote this, ask yourself whether you would applaud or criticize the same person for wearing that outfit to Wholefoods.
The tech industry is perpetually patting itself on the back for have such innovative workplace policies. Many actions or dispositions condoned or encouraged by these policies would get you fired at a Wall Street bank. So, one can not claim that one should know better than to wear these outfits. The entire point of this "new workplace", which is by definition and design not well defined, is to not dictate the individual in so far a his or her personal choices, but simply to create an atmosphere where each individual is productive.
You ever tried working in an office with a full bar on tap, twenty feet away? How about in an office that has two ping pong tables nearby in the open space floor plan? That is distracting. That is also stereotypical Silicon Valley. But hey, I put on headphones, ignored my strong desire to get bent, and was productive.
If you're a woman, please chime in here. This is, to my ears, victim blaming. And this comment will no doubt instantly begin garnering many, many down-votes. So, please, risk a few karma. But, I'm a guy, so what do I know?
I know that tomorrow I can go into work in shorts small enough to show a bit of butt and people will think it's funny, and we'll all sit down at our screens and get back to work. Because, in our culture, I'm not objectified sexually, I am the patriarch, and I control all thing, except that thing in my drawers.