Nice guy is a label used as an analogy to people some might consider safe, boring, or at worst consistent and therefore predictable. A nice guy will excuse himself politely when cutting in front of someone. These kinds of people are passively ignored, especially by women with moderate to high availability (or value if you prefer), such as never married or no children. Thing is a lot of is is walking on eggshells; double standards exist in western culture that favors the bully, the cad, the "bad boy", but this also plays on stereotypes that are often more true than untrue. So one must apparently never speak freely regarding the issue lest one be labeled a chauvinist misogynistic pig.
I see that sentiment a lot in threads like these, or more commonly in "nice guys finish last" threads all over the internet. The thing about this though is that it has become the ubiquitous go to comment that flips the simplifications back on the poster, making assumptions or implications at him, which are often just as unfair. In many cases nice guys have been marginalized, thanks to feminism. If we explore deeper we see a plethora of information to support the idea that women have many social/legal/economic advantages men do not. How this translates into the discussion here is simply that if one examines the parts rather than the whole one can see very clearly that western society is highly gynocentric; he is expected to ask her out and withstand repeated rejections while she is only expected to be asked out and decide, or he is expected to be struck in the face when she's upset and it's not okay but not really wrong whereas if she is struck in the face by him it is criminal.
I'm giving only the most rudimentary examples to illustrate my point.
In America it has become very common for women to trade up (read: hypergamy) as well as starter marriages, which are also a common trend. The other problem I see right off with feminism is that it has created a landscape of single mothers that have wasted their "first times" and "fertile years" on players and bad-boys, leaving the good or "nice guys" to pick up the forlorn pieces and be grateful for the "privilege".
Speaking mostly for myself here:
This is one of those issues where people almost always have a side they're already on and no amount of debating will change that, but when the nice guy discussion rears it's head the straw man deference to "it's not them it's you" has never sat right with me. I'm a nice guy, people have told me this a lot, and many who do so mistake this for being timid or weak, that my courteous and usually respectful demeanor is characteristic of a flaw in my ability to "be a man". I've actually said no to women more than women have said no to me, but that's because of things, like feminism, having shaped them into people well below my personal standards, such as the unwed single mother or the woman divorced before she's 25. "Nice guys" and "good guys" are often interchangeable, and while a bad boy can be a nice guy too, it's usually not the case, but rather a a lot of projecting and denial of the obvious, which is why they wind up with kids and baby-daddy issues, and why I consider such people too harmful to get involved with too personally. It really is not me, it's them.