I need to do more research into it, but part of the reason that tech workers resist unions is that they're more closely aligned with the Petit Bourgeoisie, then they are with the average proletariat.

Erik Wright argued that they even own their means of production due to owning a lot of the technology they need to produce the products like a laptop or the books or the specialized knowledge necessary to write programs.

I haven't read the book yet, I've only read some bits of this theory, but it sounds really interesting and could be one of the reasons why tech workers seem to act a lot in their own interests