This is the question that frequently gets overlooked when this whole argument comes up again (and again and again and again...)

What is the purpose the user (artist, whatever) is going for?

If someone wants to do professional quality animation or astoundingly lifelike rendering then yeah, Poser is pretty sucky.  If someone wants to get into the professional CG industry then yeah, showing your stuff in Maya or Max or Lightwave is the way to go and Poser is kiddie stuff.  If you want to create 3D objects and people from scratch then yeah, Poser ain't your thing.

On the other hand, there are a great many things that you might want to do where Poser is perfectly fine.

Here's a good analogy: there are a great many comics out there drawn by truly talented artists who have ridiculously great skill when it comes to the pencil (or graphics tablet), some in print and some as webcomics.

Then there's Irregular Webcomics, which is just digital photos of Lego or RPG playing figures.  There's xkcd and Order of the Stick, literally drawn using stick figures.  There's Dinosaur Comics, which has over 1000 strips consisting of the exact same panels of clipart and only the dialog changed.  Heck, there's Dilbert, which uses highly simplistic characters.

By any measure of purely artistic skill, those four webcomics  and one printed comic are pretty much bottom of the barrel.  But the technical skill required by the artwork (or lack thereof) isn't the point.  Order of the Stick, to use one example, is an award-winning comic whose popularity allowed the creator to go into comics full-time.  In this case the art is stylistic and plays second fiddle to story and characterization and the writing.  He's fully capable of drawing more realistically (as he does in one strip), but realistic rendering and the work that would go into it isn't the point.  Hell, in some strips he goes backwards stylistically, drawing even more crudely with crayons.  Yet the whole thing works.

Being able to make a pretty picture of a figure that you modeled from scratch, textured yourself and so on is great.  I don't have the skill to do it, so I applaud people who do.  But until you prove otherwise, all you've demonstrated is that you can make a pretty, static, picture.  Meanwhile, those pre-made clothes and textures and figures and basic lighting that the "artistic purists" complain about?  I've seen very good stories being told with them.  Individually the panels in the story might not be as technically well done but they've demonstrated a skill that the super-realistic creator hasn't.  So which is better?  Both, and neither.

Finally, some people just want to fool around with CG, and Poser is perfectly fine with them.  It's like amateur writing: some is good, much is bad, and a great deal is at best mediocre, but you don't try and pretend that it isn't writing just because there are people who are very good writers out there.