I don't like unions, either, as they tend to be very corrupt. They use union dues to fund politicians you might not agree with, and they expect you to support their positions, too.
But there is also the point that you might not get any work without being in a union. My brother had an experience a number of years ago (I'm thinking at least 20+) where he got hired as a UPS driver but there was never any work 'available' for him until he joined the Teamsters Union.
If you want to be strictly Biblical, I would stay away from unions. If that means you can't get the job you want or that you get hired but they never have any work for you, then I would start looking elsewhere for employment.