In the case of workplace conditions and such, sure. But there's a huge issue of moral hazard when it comes to unions lobbying or influencing public policy more

In the case of workplace conditions and such, sure. But there's a huge issue of moral hazard when it comes to unions lobbying or influencing public policy more generally for their own benefit, for example with prison guard unions opposing the legalization of marijuana. Locking people in cages for the sale of a relatively harmless plant might benefit the prison guards, but that benefit is vastly outweighed by the harm to society.