Ok i've seen enough of things like "pointless thread" or "why would you post this?". First off if you have a problem with the thread contact a mod so they can delete it, because their are a lot of threads that are redundant. (it is annoying when you post about a certain game and someone posts a thread about the same thing a few hours later.) (MONSTER HUNTER 3)
However if it is because you don't agree with the topic or you think it's redundant but it isn't it, you shouldn't post something like pointless thread. If the thread has been posted already then you should let them no what they did but you had better read carefully. If you post because you thought the thread was irrelevant and you were wrong, then it is your post that has become irrelevant. Otherwise you look like a jackass.
My biggest pet peeve is when someone posts the same thing i did a few hours later without looking at my thread, i get it, but to diss someones thread because you don't agree is just bumping the thread and hurting your cause.