It seems to me that this is very much the same phenomenon as people posting to reddit or ask.metafilter questions or comments that would make much more sense to pose to a particular company's customer service. People think "hey, here's a place I can write stuff", and don't really have a mental model that differentiates between targets. It's a matter of degree, not qualitative difference, between thinking you should ask Reddit why your Verizon bill is being calculated wrong and thinking of "the internet" as a completely amorphous featureless blob that you can type to anywhere and it'll be just as good as anywhere else.
I've done that with Stack Overflow; I'll ask a highly-specialized question that would be best answered by the actual mailing list, often because I'm already on SO and I am too lazy to go sign up for the mailing list.
In my defense, two days ago I tried to post to the git mailing list and it took many, many minutes to do, because:
* the git web site does not actually tell you the mailing list subscribe address; it links to GMANE and shows the post-to-the-list address
* GMANE has a subscribe option, but of course, they mean subscribe through GMANE
I finally found the master list of lists at vger.kernel.org (one giant unreadable page), which lists the unsubscribe command, which can of course be reverse-engineered into the subscribe command for that majordomo server.
And I freaking wrote a major mail server. No wonder people just post to "that place where you ask questions".
The real fun doesn't start until you tell those people they're posting in the wrong place and get a lecture about how they're reporting you to the FBI for hacking into their private business.
That is a lucid and very charitable version of my take on it, which is that there are an awful lot of stupid people about (or perhaps a few stupid people who put themselves about a lot).
Some youtube comments look like people pointlessly post their stream of consciousness to the text box below the video. A lot of search engine queries look like people are just addressing the text box as if it were a person; just like Apple is getting people to think of Siri as a personal assistant. Some day we'll have good enough AI that this will be a viable interaction method (though not nearly optimal without some learning on both ends).
I've seen reviews like this, it boggles the mind.