I used to work for a union and I helped organize a grocery store -- Jewel T -- in Philly area in the early 80s. They had just ventured into the northeast market from Chicago at the time. I organized one small store of 10 people. And to avoid going union the chain closed down EVERY FUCKING STORE IN THE ENTIRE REGION and moved out of the region. To this day Jewel has not re-entered this market. Hundreds, maybe thousands of people lost their jobs. I felt horrible, and my boss's response was "good, at least that scab chain is out of our territory."
So yeah, I know there is a dark side. There's also a dark side to management too.
But the answer is not to throw out unions, but to reform them and make them work better.