Employers don't have to recognize a union in Europe, employees can still join and avail of legal support or group actions by those employees that did join.
Similarly, if the majority of your workplace is in a union, you don't have to join, just don't be surprised they don't bother defending your case if you end up a victim of unfair dismissal. Your employer may be unwilling to offer you employment terms different to what the union employees get because of the overhead for them, but if you had that little leverage you probably didn't have the imaginary invididual negotiating power the anti-union crowd imagines anyway.