Why do you ping missing on a teammate who made a mistake?

Just trying to get some logic on this. You see that a teammate made a mistake. Usually it's something simple and reasonable, like missing a skillshot or canceling an auto. Something that was clearly not intentional. And you ping the person. Is that supposed to help in any way or make things better? To me it's one of the most toxic and childish things that people do. And from experience, it usually comes from players who don't do well in the game at all. Is it a way for you to feel better about yourself? I'm just wondering.

More examples: You fail a flash over the wall. Pings galore. Did you want an explanation of what happened? "You see, my fellow teammate, I found myself in trouble as the enemy team was trying to kill me. So I positioned myself next to the wall to prepare myself to flash over. I then placed my cursor over said wall and hit the F button, which I have assigned to be my flash spell. Unfortunately, the game decided that the wall was too thick to flash over. Alternately, it's possible that I left a bit of space between myself and said wall, resulting in an unsuccessful passage. I was then brutalized by the enemy team until I died ."

Is this the explanation you want? Because I will sit at fountain and write it out for you. Pinging things like this just adds insult to injury. I've been on both ends. I understand if your solo laner is 0-5 and keeps trying to fight their opponent after you told him to play safe. In that case it's blatant and repeated mistakes, and they probably warrant pings and criticism. But people will ping you for any mistake, even your first one.