This theme has been around the block a few times, but once again I'll throw in my two cents (or more, depending!).

Again, let me put on my kevlar, I'll probably need it.

The poser flame wars really come about because poser is affordable to the general masses.  Yes, Lil' Mikey over there who always wanted to make "way cool comic/videogame/cgi art, can ask mom or dad for it for christmas and its not outrageous.

If maya, or carrera, or others were in the same ball park price range, trust me, you'd see a heck of a lot more "crap" come out of those, trust me.  Why?  Simple my dear watson.

The more affordable, the more attainable, the more hands its in.  Yes, those with and WITHOUT a modicum of artistic talent.  Yes, thats right, a whole slew of users who want to make art, but likely failed art class (lumped in with those who didnt!).

Poser is also fairly easy to learn, click, hit a pose in the pose file,  choose an outfit, click conform to, not exactly rocket science (though it was foreign to me at first, it didnt take long).  Give this tool, or any other like it to someone who cuts off heads taking photographs....... and its a disaster.

Affordable and in everyone's hands........ the misery begins.  Now, wether hobbiest or something more, poser probably has the highest rate of "lack of improvement" of any art medium out there.  People who cant draw or paint usually stop trying at some point, but oh no, not poser users!   You can all argue if you desire, but you've all seen it.   The cruel cruel disasters of:

Sun is on the left, their light source is coming from the right........ 
Head portrait zoomed in from default pose......
Naked V3 because they ran out of clothing options..... everyone's used it before.
Gravity defyment - (fill in the blanks here, i know you've all seen it in various forms)
Michael Zen pose........ need I say more?
way huge landscape long background, head or figure waaaaaaaaay to the side

Now when we all started we're all guilty of this, and more!  The difference is over time, and with use, there is some expected (and usual) amount of improvement.  But just how the Kid that can't draw those cool anime figures continues making the same one doodle he can actually draw (or copy) with some form of confidence, ...... that same user will use poser, in the same way, and make the same mistakes every time.

No matter the medium, you either got it, or you dont.   Sadly for poser, there's a lot of don'ts.