Unions can be a problem if it's just another set of bosses who are seeking to profit from the system. So like being in a HOA where you let the dipshit homebodies with nothing better to do get in charge and start fining everyone.
You have to stand up and be involved. It's not easy, but it means that instead of being you against HR by yourself, it's you and all your buddies against HR on your behalf.
In the best case scenario, it provides a way for the company managerment to hear ideas from the employees - because a good company listens. Treat your people right and they will look for ways to make things work better and increase your profits. So it's in your best interest. Treat your employees like shit and that is what you'll get out of them.