Because I've always said that spelling or pronouncing it "poseur" is, in fact, the sign of a poser.
With any kind of pop culture genre, and within any kind of activity that could become a trend under the right circumstances, there are basically three groupings of people, all of which are, of course, wildly simplified.
1. The True Enthusiasts. These are the nerds. They are interested in subjects and activities without any external or trend-driven pressure for them to be interested in them. They think, what kind of music do I want to listen to? And they find it. They listen to the kind of music they like, and wear what they want to wear. When they come across something that's new to them, True Enthusiasts will decide if it seems interesting to them or not, and then proceed from there. The popularity of that new thing is mostly, if not totally, irrelevant.
2. The True Normals. They are normal people who are, by and large, satisfied with the pop culture materials and social events of the status quo. There's current music on the radio, and they listen to it. There are current TV shows, and they watch them. They wear whatever it's the style to wear. They don't question this very much, and why should they? Although individuals vary in their likes and dislikes, by and large they're not all that Enthused about the specifics. When faced with some weird new style they're never seen before, a True Normal will say, "Weird. I don't get it." And they won't start adopting it.
3. The Ambiguous Normals. Ambiguity is by nature not black or white, so it's no surprise that this includes a whole spectrum. They may start out with an Enthusiastic temperament that's been squelched, so they try to repress it. Or they may be mostly Normal, but have had little exposure to things out of the most main of the mainstream. In general, though an Ambiguous Normal, when faced with a weird new style, may say, "Weird." But still think it's kind of cool, or interesting, or worth trying out. In time, they may become Ambiguous Enthusiasts, or even morph into True Enthusiasts. But this is also the pool from whence the posers come.
The Ambiguous often seem particularly reactive to the status quo. For example, some people seem to be Enthusiasts, but deep down, they're driven by reactiveness: they're too angry with some aspect of society to be True Normals. They have begun to question True Normalcy. But they aren't self-directed. The classic case is people who are rebelling against their parents versus really doing something because it's what they want to do.
Among the True Enthusiasts, some of them may delve deeply into single areas of interest (ham radio, vintage Bollywood films, music from the British Invasion, underground comics), and some may have a perpetual desire for novelty, within a favorite given framework (new music, new studio arts, new experimental poetry). In other words, some are early adopters of new styles and areas of interest, while others have a narrower focus on a single area that will become an overriding obsession. Some may have started out as Ambiguous Normals who expanded their horizons and crossed over to become True Enthusiasts.
So, True Normals will watch a TV show because it's on and other people they know are watching it. Because of their personal tastes, they will still watch things based on what they like -- they're not mindless automatons! But those things will all be things the majority of people have heard of.
True Enthusiasts will watch a TV show for reasons unrelated to its popularity. They are intrinsically interested in the subject matter, or it sounds interesting for whatever reason. Or they tune in by accident. If they like it, they'll keep watching. If they don't, they won't. They will shows that the majority of people have heard of, and they will watch shows that are painfully obscure. What other people watch is neither here nor there.
Ambiguous Normals, however, may go through life watching TV shows like True Normals. But one day they may come across something unfamiliar, and react to it the way a True Enthusiast would. That is, they just like something, or are interested in it, regardless of what other people think. For a person who's used to being Normal, this state of affairs can be unsettling. They may become self-conscious. Once that happens, if they don't automatically reject the new thing as "weird," and feel they are outside the realm of True Normals, Ambiguous Normals are often confused about the nature of Enthusiasm.
By this I mean: if the subject matter of their interest is outside of Normal, something that would normally be the playing ground of the Enthusiasts, they tend to continue reacting like Normals, instead of as Enthusiasts. They continue to use the cognitive tools they learned among Normal people. Their attraction to the subject matter might really BE self-directed, coming from within. But once it's there -- especially if this is a new or unusual state of affairs -- they react the same way they would if their attraction to it were based on the desire to do what's Normal. The normal thing to do is to conform.
Only now, they are attempting to conform to a world of people whose interests aren't based on the interests of other people. Many Normals have a hard time adjusting to this. And that's where Punk Rock Conformists are born.
Some of these Ambiguous Normals may be trying out different things, to see if anything sticks and becomes a True Enthusiasm of their own. Some of them may be unconsciously driven by a desire for transgression or rebellion, and will happily turn their back on their one-time Enthusiasms, and even the idea of Enthusiasm, once it's out of their systems. Some of them may become the short-term fanatics who annoy everybody.
Only time will tell.