Unions are great when they're actually run and led by the workers themselves. But the idea of the union as a kind of permanent institution becomes problematic for a number of reasons. As you say rent seeking begins to take place with the collection of union dues, they become quasi-governmental in the sense they control the labor market and act as a kind of pseudo-tax and regulator for industry while not necessarily fulfilling their roles. Like any group of humans there is a tendency towards corruption.

Here I think this is a bunch of kids that don't understand the economic realities of the world. As a low level star bucks employee your bargaining position is very weak. Most anyone can pour coffee, including a robot.

And while there's certainly an argument to be made against the expansion of automation replacing the human element. I will remind that while I'm indeed, sympathetic to the inability to live off of a minimum wage do to high costs of living, I'm also not willing to pay a $30 an hour salary in the form of higher drink prices. Is it worth me to pay $9 for a cup of coffee vs just making it myself at a vastly reduced cost?

I mean frankly I think if they don't like the work conditions and they aren't in a good position to bargain they should quit and find better employment but telling people that anymore will get you lobbed with accusations of being mean, so whatever I guess, if they want to be retarded they can be retarded.