The joke is the poorly constructed version of a stereotype that stopped being relevant over a decade ago.
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It's poorly constructed because the joke is the nerd is oblivious/has misplaced priorities, but the joke would only work if the image showed the woman expressing obvious interest in the man, instead of having her back turned to him. As is, the image is literally just two rando's on the subway doing their own thing.
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Nerdy looking guys being too oblivious to engage with hot women stopped being relevant after incel culture, startup bros, PUA, and nerdy-looking billionaires became commonplace.
Yoga is a general stand-in for light isometric exercise. If you have a pinched nerve, adapted exercises including specific yoga poses and low-impact exercise are still recommended to help recover. For moderate exercise to get the endorphin-powered stress relief, swimming and upright/recumbent stationary cycle with good posture can be appropriate for someone with a pinched nerve.
I hate it too, but tailored exercise is kind of a magic bullet.