It's possible it's a coincidence.

The idea that scientists, especially hard scientists, have a certain look is something many think... so despite literally everyone on lemmy downvoting me, i still think it's important to notice when these things coincidentally happen or don't coincidentally happen

However you are saying SMBC is very tolerant and unbiased and I believe you. I was't saying it was sexism, I was just noticing it. But I understand the defensive reaction: if the comic creator is generally accepting of many people's identitites then they are less likely to have done this with any sort of biased intent and the comic creator is probably cool and not prejudiced.