@matigo I haven't seen too much obsessing over length limits. Some things just impose a limit. I agree they don't have to, but they do. In a way, I think it simplifies telling people what the thing is.
You distinguish social from blog-style posts, and even your social is much longer than most people would normally use. But I wonder what the average (or even median) length of post is. Allowing for obvious brevity-frequency outliers, obviously.