A bank can legitimately, not morally, argue closing an account is either a business or security decision. From a business perspective certain accounts might be deemed unprofitable, too costly to run etc. Given the hoops one has to jump through under money laundering laws/checks it would be easy for a bank to argue the individual's location, personal circumstances suggests the account might be used for illegal purposes.
I'm not defending the banks, only looking at their view.
They're not alone in this type of action. Yesterday my insurers withdrew my renewal offer. This was because I wanted to increase the insured replacement cost of my bikes. The risk hasn't changed, the overall replacement value has by £1500. All that was really required was to increase the premium but I was refused a quote. Same basic principle as a bank closing an account.