Pardoning, or rehabilitating?

The news has it that Britain is pardoning people who were convicted of sexual crimes that are no longer crimes.

But somehow, pardoning - or actually "rehabilitating"  - people who were convicted long ago, suffered any punishment given at the time, and are already long dead, is reminiscent of Soviet policies. It does not fit my idea of what Britain is, or should be.

Yes, they suffered an injustice, but retroactive changes to convictions are not that meaningful when the convicted is no longer around.

But perhaps I'm too romantic, and Britain is much closer to Ingsoc, the English Socialism of 1984, than I'd like to know.

Anyway, now comes the difficult work of deciding which transgressors to pardon (right now, homosexuality is no longer bad) and which ones to condemn even further (right now, pedophilia is now much worse crime than it used to be).

Would it not be simpler just to admit that our standards change, and any formal legal rehabilitation should be reserved for cases where there was a miscarriage of justice (an innocent man or woman was convicted), not when the law was wrong by our current standards?