Several reasons.
A judge cant tell your using your account for fraudulent activities, the bank can. The bank has an obligation to stop and report suspected fraudulent activity. The bank is in the best position to do this.
If a bank just let people use them for fraud and other illegal activities we’d have issues, the whole point is to reduce the ability for criminals to operate easily.
Its also worth noting that as long as there are no obligations to not restrict your banking, banks can refuse to serve you or remove service at any time. So if you’re seen as a high risk and likely being used to push money through the UK for criminals, your accounts going to be frozen.
Basically, if you want to keep your criminal enterprise going, don’t use UK banks. And if your expecting a large sum of money from abroad from your uncle where your not sure where he got the money, maybe let the bank know. And let him know to not use money transfer groups used by criminals to do so.