I can see the point of unions - so big companies can not completely screw over workers, who on an individual basis have far less negotiating power. However, in the country where I live, those unions that are part of the original workers movement (and usually aligned with the social democratic party) are given preferential treatment (tax deductionable membership fee, monopoly on negotiating salaries), compared to unions with a different perspective, eg. a Christian worldview. This is something I find questionable.