I've read this article twice and I genuinely don't understand why people have a problem with this.
Every year, when banks and buildings societies reveal their financial results, people wail about the obscene profits they're making. And yet here's an opportunity to put the money to charitable use instead.
And here's the killer bit. If you suddenly remember you have an account sitting around that you've not gone near for a decade and a half (and you've not lost your mind), you can go and claim it back.
Two points to remember:
1) When you put your money in a bank, it doesn't sit there, waiting for you, all cosy and nice. It's used by the bank, invested, re-invested, exchanged for foreign currencies, and worked every second of every day to make profits for the bank. So, given that, under the government's plan, you can access you money after 15 years anyway, why would you want it to keep shareholders on foie gras when it could be used to teach a disabled child to walk?
2) The banks aren't trying to relocate these customers to be nice to them. They want their customers to reactivate these accounts so that they can use the money for profit. See point 1.
So yes, just like theft. It's like someone stealing your antiques and then a generation later, when you dozily realise they've gone, you make a phone call and they're brought back to you in mint condition, having gained value. Boo hoo.