People who do this probably do not see it as a problem or are too lazy to quote properly. This quoting pattern is common in football threads, it kind of makes it difficult for readers to know who exactly you’re responding to in your post. Is it the user in quote 1,2,3 or 4? It’s even worse if there is a large image in any of the quoted posts.
I don’t think it’s necessary to quote the OP if your post is in the first 5 pages of the thread. Unless you’re responding to a particular line in the OP. I usually do not read lengthy posts, so when I see someone who’s quoted a wall of text, I tend to skip that post. So even if the comment has value, it receives little recognition because the posting pattern is unpleasant to look at.
Yes you are right, you can only see post like this in the gambling section of the football thread. I think the reason for such quote like this is because the gambling section we have thread that anyone can just come up with a particular topic or sport news. If the the news is an interesting their will be a lot of quotes because the discussion is an interesting one and many people just want to add their contribution about the discussion. It is only in the gambling section you can see quote like this and I don't really blame people for this because gambling discussion is a very interesting one that many people would want to contribute on discussion for a very longtime.
Despite that the gambling section is an interesting place for sport discussions, people should learn how to quote one after the other to make it easy for people to understand and for the sake of to make quoting look good.