I think you missed the point of a TL;DR. I have always treated TL;DR as an abstract to a paper. It kind of sets the stage and presents the conclusion in a concise way so that if one is still interested in the full content of the paper, they can read in depth. For example, if the title is interesting enough for me to get to the page/post. The TL;DR basically packages and refines the crux of the topic so that I can get the gist of the post.

Of course, it would be plain stupid to try to get involved in a discussion without actually getting into reasoning for the conclusion but then there is no solution to stupidity.