So the article seems to present the typical argument against unions, i.e. "they protect bad employees", but ultimately the story concludes with the creation of a new union that negotiated an improved and ostensibly successful deescalation policy as part of the labor agreement. I don't think article presents a convincing case that unions are the problem.

I gave you the link that was closest at hand. There are many. For text, try https://www.buzzfeednews.com/article/melissasegura/police-un...

For video, and I highly recommend this, try https://www.youtube.com/watch?v=Wf4cea5oObY

But if you don't like BuzzFeed or John Oliver, it's trivial to find articles about the harms caused by police unions from sources across the political spectrum.

In the abstract, conceptually, unions aren't a problem. I love unions! But police unions have such a long and consistent pattern of making police worse that I'm not sure any police union can maintain good things for more than a year or two.

I would be pro-police-union if police unions worked like all other unions, fighting for better pay and conditions for their members. That's just not how police unions work in the USA.

P.S. As you say, the article mentions a new police union that so far seems to be okay. It should be noted that union was formed after completely dissolving the existing police force of Camden, NJ, and all of its contracts, including the contract with the existing police union. Time will tell whether the new union starts to be a problem or not, but certainly starting under the threat of "act up and we will dissolve the entire police force again" is a good start.