I think the point is that this kind of activity creates a marketplace that makes it easier for potential terrorists to launder money. If people are openly breaking AML rules then a terrorist can see this and purchase a lot of bitcoin without anyone thinking twice and then potentially being able to use that bitcoin to pay for a potential terrorist attack.
With that form of reasoning one can justify anything - anything at all.
For example: if people are allowed to get into their cars it makes it easier for them to drive to the location of potential terrorists and assist them in some way. Therefore people must not be allowed to get into their cars.
I believe that people are being manipulated through use of the T-word bogeyman into doing and tolerating some reprehensible societal changes.
Time to read "1984" again, lest we forget.