I've run track and field, been in twitch chat, I've played soccer, rugby and football, and I've been on 4chan a few times. This copypasta is kind of ubiquitous. When I was running track, or after a 5k comment thread, this copypasta was the most reasonable and easiest way to congratulate somebody. Most of the time they'd either be bent over sucking in air, or with both hands on their head trying to catch their breath during slowmode. A good copypasta is something they'll feel and it doesn't require their attention, and it's well understood as "Great fucking job". As for reddit, after gold, celebrations get crazy. Usually the gold-scorer is being swarmed while they themselves seek out the redditor who guilded them. Generally speaking, people have two old, reliable copypastas, and there's 11+ people on reddit. Everyone wants to get a congratulations in so there's a lot of copypasta being copy pasted. Even after a good comment the other commentors will usually move in to copy and paste their copypastas for the one who made the comment. IRL everyone's wearing pads and a helmet, so the eyes are really the only exposed part that's open to a copypasta, plus with huge threads, you usually tend to get huge lines of high-fives and copypastas. So, in short, because the copypasta is always a viable option, it doesn't require mutual attention, it's not very involved, and it's a guaranteed way to get attention.