"We [..] believe in the right of all employees to decide whether or not to [..] vote for a union"
Right up to the moment some of them decide to actually do that, at which point it's no-holes-barred intimidation and harassment tactics until they abandon that idea.
And I love the argument of "19 employees should not be able to decide". That is a typical strawman argument. You pretend that you want all employees to decide, but that is just an excuse to bash those who do.
And, as far as the USA is concerned, you can replace Activision with any major corporation, they all behave the same on unions because unions will force them to spend more money on their employees and the Board doesn't want to do that (eh Amazon ?).
Now contrast with Luxembourg. In the 1990's I was working my first job as a junior consultant programmer in Lotus Notes. The company was called Computerland Europe, and, at the time, it was going forward in leaps and bounds. New employees were coming in practically every month. It didn't take long for us to reach 50 employees and, when that happened, we were all called to a meeting by top management. In that meeting, we were told that, having attained and exceeded the magic number of 50 employees, Luxembourg law mandated that a union be formed. Our CEO thus told us that we were to form our union right there, and management left the room.
We looked at each other in total surprise and, for some, a little bit of shock. Nobody had been expecting that. So we went about to create our union, electing members (I was one) and following the charter that management had transmitted to us.
And what did this union actually do ? Basically, we made sure that security measures (fire) were known and respected, and being available if any employees had a complaint. I wasn't there long enough for that to happen, the company was still on a meteoric rise. That's not generally the kind of period where employees are unhappy because everything is always changing for the better.
Besides, in Luxembourg before 9/11, if you were unhappy at your company, you could just find a new one, simple as that and almost everybody did it.
So I'm quite happy to work in Luxembourg, because my rights as an employee are enshrined in law and no company can escape that. Of course, there are always the few who try, but they end up against the ITM - l'Inspection du Travail et des Mines and, having done some work there, I can vouch for the fact that they don't pussy-foot around with employee rights. If you have the proof, that company will pay.