Yes indeed, due to many assumptions we may be considered not knowledgeable about things that are not our usual forte. In the thread you mentioned, it is possible that the bug (I think when any of us talk in the forum about a bug we do mean a technical glitch) was a result of the new template. Perhaps some feature of the new template created the glitch. How would we know? As you said, the Webmaster did not give the cause of it since it is not necessary that he would need to do so.
In the thread, on the face of it, it does look as though it was implied "You don't know a jot about technical stuff. Why are you responding?" Perhaps the wording in the response was interpreted by you like that. Keep in mind, though, that just as you gave your opinion, so also did the author of the thread. It is not necessary that the thread author's will agree with those who respond and vice-versa. That is the beauty of the forum - we can all agree to disagree but have a perfectly amiable discussion on it. We've all, at some time or the other, experienced such assumptions. The real fact is that everyone just has their own manner of conveying something and words may often get misinterpreted, maybe more likely due to the tone in which it is conveyed rather than in the literal sense of the message conveyed (there - I am assuming the reason!)
When people come at you with their worst, you should come at them with your best (advice given to Selena Gomez by her mother, quoted in Time magazine.)