Why does having different values imply intolerance?

For me it isn't much intolerance, it's more of a lack of patience for the careerists.

Working with people that love what they're doing can be very chill. Working with people angling for a promotion, taking shortcuts, one-upping the co-workers and still not pulling their weight is exhausting.

This is not a new phenomenon, in the past this kind of dev also existed. Lots of people studied CompSci but didn't want to be a "lowly developer" for long and were just making time to "become a manager". Of course they never put the work for that as well. Today it's half of the people I interview: they never got good enough to become a manager, and never become good enough to pass most interviews in the market of today.

On the other hand, I got a couple manager friends who love coding and are trying to become individual contributors, but keep getting pulled into leading projects because of their expertise.

Don't get me wrong, though, everyone wants to make money and have a good career, I just prefer working with a different kind of person.

I do think there can be element of snobbishness around it, but that's not really the point. The overculture of corporate America has finally overtaken the hackerish (relative) meritocracy of early tech, of Getting Things Done and Building Cool Stuff. Rewards are increasingly tied to metrics decoupled from useful outcomes. If you want to get paid a big tech salary you need to go through the leetcode grind, and do things like project sufficient "masculine energy" (lol). Management performance is measured by hiring and expansion more than product delivery and success. The ethics of what you are doing are completely secondary to shareholder value. You still need technical skills, but they are somewhat less important, there are many more competing incentives than there used to be, and the stakes are higher. This has been happening since the early days - cf. Microserfs, written all the way back in 1995 - it's just that tech has worked its way so thoroughly into the fabric of corporate existence that the two have more or less completely merged.