Earlier quoted context omitted.
Is joining a union in your country mandatory? (or can be made mandatory?). I am not talking about peer pressure but legal requirements. This sounds quite crazy. What if there are 5 unions like we have in France?
Not at the Country level, but unions have been able to make it mandatory in certain industries and companies. It is how they hold their power. If it was optional, they would whither away over time.
In France unions are optional (in the sense of adhering to one, their presence is highly regulated and a company cannot do anything against that). They are quite strong (depending on the industry), and representatives are elected.
If a union does not do anything then it indeed whither away.
Now - in our case, some situations are a parody (especially in some places like positions in the administration, the famous fonctionnaires where everybody is on the street when the post office is required to be open outside the times "10:30 to 12:30, except on Mondays", for which their ancestors fought :))
We have a love-hate relationship with unions (which of the love or hate depends on whether you need to take a train and you forgot that there are only 126 days in the year when they are not on strike :))