~snip~
Obviously OP you have a good point but your post lacks quality from my perspective but maybe not in others perception. It's not well constructed but it's surely passing an information. Sometimes I don't blame people for making off topics post in a thread but at the same time everyone is entitled to his or her responsibilities which means you have to read before you make a post.
Reason why I don't blame some people for off-topic post is because some people don't follow the etiquettes of the forum for creating a thread, they just type what's in their head and click post without proper reviews to ensure if it is making any sense or follow the forum standards or not.
Include enough info in the title so that readers can mostly guess what your topic is about. Try to condense your topic's main idea into a few sentences. Ideally, people should be able to write useful, on-topic replies by just reading the title (though this sometimes isn't possible).
From the above quote especially the bolded part, one should be able to write on-topic post or response just be reading the title of a thread, so where people begin to write off-topic in a thread is when the topic says some thing else and the content says another then it will have to require someone to read deeply to write an on-topic post.
For people especially newbies who will want to read more on the above you can visit this thread
Make your topic title, posts more attractive by @tranthidung or click on the quote to read the complete post by @theymos
Regarding the second paragraph of OP's post, some times I see paraphrased sentence in a post though I'm not excluded to it but almost everyone is included in this part but sometimes it's necessary to add at least a line or two to a post as long as you know what you're saying even though someone might have said similar thing but with your own point it could be elaborated.
Let's say @LoyceV doesn't like writing too much on a post he prefers hitting the point straight and he already responded to a thread and I'm interested in it, I can elaborate his point as long as we are saying the same thing hence I don't consider it repetition words because it brings out the real ideal of a short sentence.
We have different perspectives of things but I guess this is mine.