[...] one but may have stopped many others where the difficulty in obtaining a firearm was the difference between an angry post on Facebook/Twitter/Livejournal and 9 dead in under a minute.
I can think of two in my lifetime. The one you mentioned in Utrecht, and the Alphen aan den Rijn one in 2011. Even accounting for population size it's nowhere near the severity/frequency of the US.
> Gun control did nothing to stop that.
Gun control obviously isn't going to stop every attack. That doesn't mean it can't prevent many of them.
Don’t forget everything that isn’t covered by the media. In 2018 we had 527 registered shooting incidents. In the last 18 months we had 44 gun related deaths. In 2018 the police seized 76 automatic weapons such as the AR-15.
For a country with strict gun control that’s a lot.
You need to fix the rotten mentality that has corrupted many American brains. That's the reason we have so few mass shootings in Europe. Quality of life is much better, for starters.