People post tracks for various reasons. Sometimes it’s to get feedback to help them make it better, sometimes it’s purely to show their work in the hopes that others will enjoy it.
I think to take the position that people who post unfinished work is somehow lazy or otherwise negative is a little strange.
I mean, if I were to take a similar attitude to the theme of your post I might say that it’s a half-finished idea… not properly thought through before being posted here and conclude that you are being lazy. But I don’t take that view, instead I see it as a discussion where (due to the nature of forums) people feel it’s normal to contribute ideas without necessarily offering a definitive conclusion requiring no further discussion.
And besides, art is never finished only abandoned.
I don’t see it as lazy, not at all. Nor would I say negative either.
However, in the context of a public audience (ie: casual music listeners/punters as opposed to musicians/producers/engineers etc) i think it can be increase the possibilities of being detrimental, if only on a minor level.
In this context, what the casual listener first observes will often be what sticks.
Much the same as when meeting someone for the first time, a person makes an impression in the first few moments.
It is not impossible to counter this, it is just difficult and I prefer to avoid it if at all possible.
Each to their own though, just my 2 cents. by no means do I see my opinion as conclusive. It is but a mere opinion 
Never finished only abandoned indeed and to add, process is the most important part
I’ve just started reading “Zen and the art of mixing” which partly goes into the psychology of creativity. Seems like a highly recommendable book so far that puts things in perspective. I’ve learnt some very valuable lessons only from a few chapters.
My interpretation is that posting WIPs is often an attempt to relieve the internal pressure that often comes with creating something. If the pressure becomes too high, you might seek external validation. Therefor: a better approach might be to disregard pressure (especially as a motivator) in your mind from the start. Make music production something fun and exploring. Post a WIP only when you’ve come as far as you can and really need some input or feedback - i e when you lack vision.
Interesting perspective. On a similar tangent, committing to finalizing something I believe builds confidence. To seek guidance and reassurance too often may illicit stagnation and indecisiveness. it may also stunt progress by developing a codependency on such a validation.
It can be possible that it is beneficial to some, though personally I would prefer to submit a track I considered finished for critique, then if i felt the response drew my attention to something i may have not considered, then I may rework it.
Although nowadays I am pushing myself to commit to finishing and just being content with it being the best I could do at the moment, regardless of how I feel in future. That to me, seems the most logical way for me to progress.
We all seem to have our ways of working, there are no rules set in stone. If there were, no doubt at some point they would be broken 
