People don’t say tldr if they aren’t trying to insult you. They just delete and move on.
You've misunderstood what "TL;DR" means. It means the writer thinks their *own* post is too long, so they're providing a short summary for those who don't want to read the whole thing. It's like "SKI" (summary for the Klingon impaired), except for the time-impaired instead.