"it's a meme" isn't an excuse for not giving credit. If KC Green made an image macro and posted it on Reddit it would be one thing. But they didn't, they made

"it's a meme" isn't an excuse for not giving credit. If KC Green made an image macro and posted it on Reddit it would be one thing. But they didn't, they made a comic and put it on their own site. I can't speak for KC but it's just bad taste not to cite things that are flat-out copyright somebody else.