This is exactly the problem. Many of the unions I mentioned above are such ones, where in many places, you must be a member if you work in an industry. They are less unions and more guilds. Let's say you are a carpenter, a skilled trade you have likely spent a large number of years learning. It's quite hard to leave the union, because you will be forced to move to a different profession. This obviously isn't right. Unions can serve a purpose for collective bargaining; I think most agree on that. But they don't need to support political parties.

It seems that some unions have shifted from representing employees in negotiations to representing a profession in all respects. I believe that's contrary to their original purpose and dilutes both their support and their credibility as simply advocating for the worker.