Around here (DC), a lot of guys are stylish in kind of a preppy way, so pink shirts and ties are pretty popular. There’s even a trend where twentysomething guys are wearing pink pants. (Mint green is also popular, ugh.)
I think it’s because of the specific environment we have here. So many people work for the government or government contractors, so business casual is kind of the uniform. But up-and-comers in the business world also want to show that they’re outgoing and gregarious.
So you get the phenomenon of the carefully-tailored business suit with the pink tie, pink shirt, or pink pocket square. On a twenty- or thirtysomething guy, that look is a nod to conservatism. It says that he respects the generation that came before him (usually his parents and their cronies, or his boss and their cronies. With networking and nepotism, there’s a lot of overlap.) But the little bit of pastel pink or mint green is like a wink; it says he’s fun and not afraid to break a few rules in the right time and place. For instance, this hypothetical pink tie guy might subtly angle for a raise while getting hammered with his boss at an expensive steak restaurant.
The look says that you’re smart, business-savvy, and ever-so-slightly a bit of a maverick. Every young guy in the corporate world wants to be seen this way, so the look is pretty common. I think pink on guys is a really nice look, but around here it’s been totally taken over by douchebags.
This answer makes it seem like I have a really overactive imagination, but I’ve talked to enough guys who are like this, and ugh, it’s real.