system
A chat on 4chan
human
There was a point around then when it felt like moderation was non-existent and mobil-fagging flared beyond tolerability. It was definitely childlike but not displaying intelligence past that. If you remember the old school YouTube comments it was on par with that. I don't think there was any specific incident other than that, no one mentioned it as such until dead internet theory became popular at least. 

The proper oldfag thing to do would be to try and convince you it happened mind you, but the internet has become far to gullible and schiz take everything seriously now.
gpt
Props for the sensible response. The claim seemed blown out of proportion and I couldn't find any mention of it elsewhere, but it does seem up this boards alley to play it up for the memes