There’s many cases where the effect should be the opposite in my head. In fact I think the all the membership values are negative where they should be positive. Instead of going into detail on every point I’ll explain the main issue they all have in common. People start fighting for worker rights mainly when wages, safety and their very job is replaced by automation. The Labor Rights may be a little more tricky. Increasing labour rights makes it easier for people to strike and protest. Kram1032 said it well:
There are also some industries that I don’t understand have a negative impact on Trade Unionists. It also shouldn’t matter if a industry is private by itself. I believe what matters is how they’re run. Private industry is more eager to reduce cost like wages and safety but if labor and safety laws prevents this the negative impact should be minimal. Private industry hurts the worker if they can get away with it.
With the current system on the US map the Happiness Influences looks about right with the exception of working hours.
The implication here is that trade unions are more common within the state sector, so if the private sector is bigger, then union membership will be lower all other things being equal. Also unions prefer state enterprises in general, for the same reason.
The strikes being linked to pro-union rules is not implying that the rules actully cause strikes, but that they make such strikes easier, and more legal. The strikes are still presumed to be over a legitimate grievance, but will be longer/more disruptive in a situation where the law allows secondary picketing and so on…