Can someone explain why do they need a union when they work for a non-profit? Aren't they mostly volunteers?

From my experience in my youth volunteering at animal shelters and environmental protection groups, you never volunteer for a non-profit for the money or the job stability, but you do it for the mission and the satisfaction of being the change you want to be in the world, even if that means living off ramen and beans and couch surfing. Especially given these are cushy jobs done from the PC via the internet without needing to physically get your hands dirty or break your back in poor working conditions, which a lot of other young well intended and ambitious people in the world would like to do, even for free.

Everything I've been reading in the last few years about wikipedia's management, article moderation decisions, political side-taking, and how they spend their donations has been very fish smelling and off-putting. It's like there's a malicious Hydra in the basement, wearing the Wikipedia name I grew up with as a skin suit, to advance their goals and agendas. Very fishy. But it does feel like this is the inevitable faith of a lot of old and famous non-profits over time, as the gray-beard founding staff leave and get replaced by people who don't share the same values and mission, but have their own agendas and wish to co-opt the established name brand and influence that comes with it to push it. IDK if this unionisation push is for good or for bad since I'm not a fly on the wall at the internal meetings to know the internal drama and gossip, but I do remain skeptical about what's going on at the WMF.

Like maybe the union is well intended today, but will it be the same in 10-20 years with that power? What protection are in place they don't misuse it? For a global repository of knowledge like Wikipedia, I'd much prefer the staff be constantly changing with new ambitious innocent blood, rather than have an entrenched gerontocracy protected by a powerful union, since from my historical knowledge I've never seen that end well long term since long reign and absolute power corrupts.

My 0,02$.

Nonprofit doesn't mean you don't pay your employees. Nonprofits earn and spend money like any other corporation, including paying permanent fulltime staff. Not everything can be done by volunteers. What they don't do is reward their investors with a cut of earnings above expenses.

They are not mostly volunteers. Editors are largely volunteers, but administration and development is very much a financed pursuit.

The nonprofit board can provide some oversight, but bringing workers voices to the table can provide additional perspective.