"100% of workers have heard about the proposal. 30% (just, scraping the barrel) are in favour. 70% of the workers are apparently actively against. Speaks volumes."
Not really. Just because 30% are in favour does not mean 70% are against. Part of that 70% may be scared of losing their jobs for declaring "for". Part of that 70% may be on the fence about the whole thing. Part of the 70% may be completely indifferent to forming a Union. Part of the 70% may not even be aware that a proposal was put forward, or what that proposal entails.
You have implied a singular set of behaviours from an absence of information. Where is it explicitly stated that 70% of the workforce are "actively against" the proposal?