As someone who works at a financial institution, it's news generally because money laundering activity tends to be highly profitable for banks, since they get to collect fees on those transactions. There are almost no incentives for us to flag transactions on our own (unless we're being super humanitarian) without legislation/regulation, because as long as they get their money there's no downside except for victims o…
Of course, if I tune my cynicism level a bit darker that line of thought breaks down again, because then I start factoring in the possibility of "premium service tiers" with fees so high that a) no client in their right mind would ever consider them unless they have very pressing reasons to be friendly with the bank and b) no reasonable finder's fee could ever hope to win the bidding.