It doesn't look like it's accurate to say the origin of the meme is a reddit thread "where users egged on an angry man whining about an ex-wife named Karen." If that was the case, I'd find that legacy of misogyny hard to stomach, but it seems a lot more complex: https://www.insider.com/karen-meme-origin-the-history-of-calling-women-karen-white-2020-5