If you're a bank, your services will be used to launder money. It's guaranteed to happen. All you can do is implement controls to keep that activity below a certain threshold. And banks reasonably want to implement as few controls as they can get away with while complying with the law, because it costs them money to do so. Failure to implement sufficient controls for compliance is not tantamount to an intent to assist money laundering.

There's absolutely no parallel here to the situation of ordinary people. If you see that Joe Schmoe's bank account was used to launder money from a drug cartel, you can very reasonably infer that he intended to assist that cartel. There's no reasonable explanation that involves trying to save money or hassle on regulatory compliance issues. Those sorts of transactions don't just accidentally or incidentally happen to ordinary people.