Sometime people troll by sealioning: http://wondermark.com/c/2014-09-19-1062sea.png

(I'm not accusing the granparent post)

Unfortunately, asking questions on the internet is often seen as "opposing" or "arguing against" the thing you're asking about. So many qualify their statements to avoid this sort of misreading.

It all depends on the tone of the question, which is hard to discern in writing, so the clarification is helpful.

Edit: Yes, those are very valid and reasonable questions. Clarifying that it's not meant as trolling is also valid and reasonable, because writing is easily misunderstood in exactly that way - which is the reason smileys were invented. (And, to be clear, I'm not accusing anyone of missing smileys or of trolling. I am trying to express my agreement with both parent and grandparent.)

Communication by writing is harder because you miss facial expressions. Because of this, a lot of it is subject to interpretation on the part of the reader. The tone can be inferred from a lengthy piece, but not so much from a small paragraph.

So, in order to avoid bias on the reader part, I preferred to explicitly tell it was not trolling.