Violating sanctions is a big deal and a risk no business wants to explore. It’s unfortunate but true that most of the automated solutions have a very high false positive rate (sanctions are way more expensive than unhappy customers). When I was at jpmorgan I was told there was literally an entire campus in Florida for double checking every flagged transaction.

Tl;dr it’s expensive to run any sort of zero false negative, low false positive screening process without a lot of dedicated engineering and manpower, and if you’re not a bank you’re gonna do a scheme that’s got a greater false positive rate to keep the costs manageable