I deal with a union and my employees and it's a fairly "benign" union. That said:
1. Unions cater to the lowest common denominator; all they care about is seniority and individual performance be damned.
2. There is a reason as to why union membership has declined from a high percentage in the 30s to less than 8% today
3. Their real motto is "pay me more so I can work less." And if you've ever been around a port and watched line handlers, it's patently obvious...
I disagree somewhat with your first point. I do agree seniority rules absolutely with an iron fist. In regard to individual performance, the union will shamelessly use the superior work ethic of a small group of workers to justify inflated wages to the whole group.