Who else would they work with in the USA? - as far as I know the civil service unions in the USA don't have members in the private sector.

Spin up their own unaffiliated union?

A few googlers teaming up can presumably afford to pay some labor lawyers to draw up the paperwork and guide them through the process. It'd also leave googlers' more in control of their destiny than quickly becoming a franchise of a larger union.

With the hundreds of members they now have, they could cover a few staff and/or consultants. Maybe even with some sort of loan to the union for spin-up costs that could be repaid from future dues if successful?

UAW is another common choice, but they have a terrible track record of squashing workers rights in the University of California system. (Read up on the 2020 UC Santa Cruz wildcat strikes, or when they negotiated to reduce health care coverage for female grad students and also forced student salary caps through a decade or so ago.)

Why work with any of them?

The IWW for one.

They don’t know what they are doing or what they want. Some of the main organizers are 1-2 years out of college and this is their first job. It’s really silly.

How does this being their first job out of college mean anything? Do you have to pass a certain threshold before you're allowed to unionize?

Experience would help, especially when dealing with old, politically-connected organizations.

Going on their own would probably also be hard, since union laws in the US are complicated.

None of this stuff is taught in engineering courses in college. I think lack of real world experience is a pretty good explanation. Hopefully they can course correct before it snowballs. Finding a trustworthy old-hat union organizer or ten, and having them act as an advisor might help.

It tells you what kind of life experience they have to inform their decisions, including to unionize with a job like that to begin with. I think it speaks for itself.

The Activists or the Fulltimers? :-)