The author is reflecting on opportunity costs and the dysphoria generated by an anxiety-inducing rewards system which pays out randomly huge amounts to people who don't seem to deserve it, while inflicting a lack of control and ownership on others. The title reference to the "uncanny valley" points out that working for a Silicon Valley startup is marketed as a fulfilled lifestyle, providing a sense of accomplishment in solving real problems and just about everything you could imagine if you work hard enough. But it turns out to be an illusion, eerily close to the real thing yet ultimately unsatisfying and false.

https://en.wikipedia.org/wiki/Uncanny_valley

To make things worse, the startup life is so seductive and demanding that it excludes a lot of other potentially rewarding life choices which the author's peers enjoy. The author feels that startup workers are victims of operant conditioning and lack real independent agency in their lives.

https://en.wikipedia.org/wiki/Operant_conditioning

It's been pointed out that unpredictable rewards really screw up brains, causing them to obsess over the payout despite the overall returns being low. The author feels that startups and gambling have a lot in common.

https://en.wikipedia.org/wiki/Compulsion_loop

In the author's case, the conditioning is so strong that, when she thinks back on her experience with the startup, she's still seeing herself as part of it even three years later and she still feels the same compulsion.