There is nothing inherently undemocratic about unions so long as they abide by standard democratic rules: members vote on important decisions (in particular contracts) and voting is conducted through secret ballots to avoid intimidation. If a group of employees wishes to form a union in order collectively bargain with its employer, this may be good not only for the group but also for the employer.
However, some jurisdictions have undemocratic laws regarding unions. It is not reasonable that a group of workers should be able to form a union and then force those who oppose the union to also contribute fees. Workers who wish to retain their individual rights to contract with their employer should be allowed to do so. One of the biggest problems with forced union fees is that it becomes almost impossible to dissolve the union even if a majority of workers wish to do so. With anti-union employees unable to vote because they refuse on principle to “join” the union, the pro-union contingent controls the future (and the finances). This is not only undemocratic it is prejudicial against the anti-union group.
Jurisdictions which have “Right to Work” legislation are more fair minded. These jurisdictions protect the right of workers to form a union but also protect the rights of those who wish to retain their individual status. This is a more balanced approach to employee rights.
Pro-union activists will no doubt think this posting is a political argument, but it is not. This web site is about democracy and how to make politics fair for the electorate as a whole. We do not believe that forcing employees to pay fees to a union they do not support is fair, although we wholeheartedly support the right of workers to bargain collectively.
Another important point to make here is that unions arose because employers were unconstrained in the way they took advantage of employees, especially through unreasonable and/or unsafe working conditions. In most jurisdictions the government has legislated minimum employment standards, somewhat marginalizing the role of unions. This does not mean that unions have outlived their usefulness, just that their role needs to be redefined.