Is your answer driven by real data about the decision making of banks?
Do you have anything to back this up? What I am asking for is specifically does the usage of an OS other than the preinstalled one have a causal, direkt link with the user's bank account being attacked and money being stolen from it?
Direct specific evidence to back up the criticism that these guys are not looking at data and just making up dumb rules to reduce their customer base.
It is on you to back up your claim.