Have anyone noticed that the reason why some persons post go off the topic is because they don't read the entire op writing before they reply to a thread, some persons respond to a thread based on the caution of the topic and that is why we meet up different opinions or suggestions that is not in lines what the OP points of view.
Secondly, when someone have written what you want to write in same thread you have to give off, instead of making a pointless point, I know very well that many users in forum make off topic because what I outlined.
I agree with you but sometimes the title of the thread has nothing to do with the topic, so unfortunately I think sometimes people want to say something about the idea in title but after reading the topic they realize their argument has nothing to do with actual subject of the topic