It means too long didn't read. I make an honest post asking for a loan and I only get sarcastic replies putting me down. If I said what I wanted to say right now I would get banned.
My post was not sarcastic tbh. If you post 20 line line paragraphs nobody is going to read it unless they are looking for entertainment (trolling or being trolled) or to respond with an insult. That's the reality.
Get to the point, make it easy to read, or your message whatever it was (and I don't know because it was tl and I dr), will be lost.