A union can limit their involvement to strictly salary negotiations if it's members choose to do so.
I think in theory people can band together and collectively negotiate without actually forming a legal union.
The framework to band together and collectively negotiate is literally called forming a union.
You don’t have to collect dues if you don’t want/need to, nor do you need a bureaucracy.
Eventually groups of collective negotiators (unions) end up in situations requiring resources, which require money. I’m talking about simple lawyer consults or if you wanted to buy research on current market pay.
This isn't some cooking eggs and not calling it frying. This is more you not understanding. Failure to comprehend and being mean is what's going on with you. The term is ass hole. Because let's face it, there's no failure to comprehend here, just deliberate pedantism and mischaracterization.
https://www.nlrb.gov/about-nlrb/rights-we-protect/the-law/em...
It is this legal definition of a union that has the ability to characterize your membership in the legal union as having paid union dues.
This legal formation of a union which is required to even sue the company isn't required for employees to act collectively.
But you know this. It's obvious. Stop being deliberately pedantic. Just move on man.
Unions are for people without options.
Unions exist so that the people with options can help the people without options.
Unions are meant to be a tool to increase your power by solving a coordination problem between employees, and there are many examples of them working well for that purpose.
Additionally in the current market for the past year, software engineers aren't getting hired as fast anymore. The crazy hiring has slowed down and many companies are actually offering lower salaries. It's much harder to land a job.