This isn't the first question where I've seen this done, but the moderators removed "Hello" and "Thank You" from the question. I can't seem to figure out the reason this is done. Maybe a moderator can shed light on this?
Yep, it has nothing to do with politeness, its simply a matter of removing noise from questions.
Another good reason to not begin with "hello" or similar, is that the first part of the qestion goes on the preview list. If what people read is greetings instead of the question, this lessens the chance that a potential answerer clicks on your Q and tries to answer it.
Back in SharePoint overflow we had a user who insisted on introducing every question with 3 lines of mentioning what his setup was. This was annoying since you could not tell what his Q was about without clicking on the Q.