ok, I have to address the elephant in the room: is the bad image quality intentional (part of the joke) or not or what is going on here?

in case it gets fixed, here it is right now:

TIL that there is a 2x size version of many xkcd comics, which the explainxkcd bot seems to have downloaded and which looks a lot better: https://www.explainxkcd.com/wiki/index.php/File:superstition_2x.png / https://imgs.xkcd.com/comics/superstition_2x.png

edit (c. 9 hours later, the morning after in my timezone): ok, it seems it has been fixed, so it was apparently not intentional

It's because we're just pattern recognition machines and a false positive is better than a false negative.

So if an act might result in a positive or avoid a negative, it's safer to just do it anyways. Giving people who get neurotic about it enough of an evolutionary advantage that it's still relatively normal human variation.

Maybe the environment changes to where that OCD behavior is really advantageous, then the rabbit rabbits will inherit the earth.