Many people who have never been in close proximity to programmers think that the only prerequisite for becoming one is that you have to like computers. As anyone even slightly more experienced could tell you, that couldn't be further from the truth. For starters, you've got to have a heck of a lot of patience, and an eye for detail that can pick out those tiny but often mighty mistakes. Depending on the type of coding you're doing, it can help to have a creative mindset, and if you do it for a job you also have to learn to manage the expectations of all the non-tech people who rely on you. It's a lot!
This makes it necessary for the coders of the world to have a way to vent, and memes about programming are probably the most enjoyable way of doing that. They're yet another great thing that has been facilitated by computers.