Why do girls focus so much on their weight? Well, let me tell you this - after taking off 18 lbs in the past few months I feel a lot better. My BMI is no longer considered obese, but it is still overweight. I'm not thin, but I'm making progress. My clothes are looser and don't hurt me by mid-day.
Now, when I go shopping looking for a flannel shirt (which is back in style, welcome back Nirvana/early 90s bliss) I shouldn't want to cry in the store. Of course the women's cut stuff doesn't fit, I expect that. But the men's too? Seriously, an XL men's shirt should NOT be too tight for my arms to bend. This "skinny" trend has gone way overboard. Men should not be that skinny. Pick up a weight, heck pick up anything and you'll have larger arms than what this shirt would permit.
I don't know if the designers are obsessed with the 12 year old boys in china (where the clothes are probably all made) or if the crab-people are real (reference Southpark) and planning to wuss-i-fy our country to the point of being easily overtaken.