Here is the problem. As this article noted, unions are among the top contributors to political campaigns. In the case of government unions, they are donating to someone who might well in the future be across the table from them - so, given the power that government unions now exercise in the political process, it means the union has representation on both sides of the table, which has led to the massive increases in pension and benefits costs to taxpayers. That is the greatest problem here - the unions in that situation have just as much ability to be abusive as employers were 100 years ago when they controlled government and law enforcement. As long as government employee unions are so deeply ingrained into the political process, it is not an unreasonable demand to remove their collective bargaining capacity.
To further reinforce your point, one of the most egregious aspects of the public employee union/Dem politician relationships is the way unions have negotiated the benefits part of their package.
Invariably, they have called for huge increases in benefits (which now approach 50% of public employee compensation), but have agreed to irresponsibly low funding of these benefits.
Thus, they were able to manipulate the relationship -- vastly increasing public employee compensation while allowing the politicians to reflect only negligible current costs to their budget. The enormous future liabilities were buried under the rug -- in a manner that any private sector employer would be charged with pension fraud.