Q: is the Utrecht shooting a case of "they knew and they let it happen'?
Exactly. Turks rioting in the streets of Rotterdam just before parliament elections. And yes: it's known that the use of force against the rioters was used by the establishment to bolster their image.
And yes:2 days from now we have Senate elections. And now this happens! I find it hard to swallow this is a coincidence. And yes: Dutch PM immediately came with a press conference. And immediately it's describes as a terror attack. Usually they would belittle it.
I just don't understand how the establishment could benefit from today's attack. If anything - this attack should benefit Geert Wilders and Thierry Baudet. We'll see how it unfolds.