Earlier quoted context omitted.
When I worked at Boeing, membership in SPEEA was optional. They offered benefits to paying members, but the benefits I received as a "free rider" were pretty minimal.
The real benefits will be things like a decent contract with e.g. proper treatment of overtime, sensible safety policies and so on. Which you absolutely get to free-ride on.
This is like saying Joe 401k is free-riding on Goldman Sachs because Goldman tries to find the right price while Joe 401k just takes whatever price is available.