The genius mathematician should be celebrated for his achievements, not his legal victimisation.
Politicians apologising for things is not only ridiculous but offensive. Tony Blair apologising for slavery makes a non-sensical claim to responsibility that trivialises the slave trade. That entire chunk of history in which hundreds of thousands of people were condemned to nameless obscurity and misery cannot be undone by apologising centuries later. It might make everyone feel better about themselves but that's why it's so damaging. The history of slavery should stand in its entirety. No one has the right to apologise for it and doing so just recreates the unjust orchestration of the history of nations.
Alan Turing was pardoned. Pardoning, according to OED, means that the crime he committed still stands, he has just been absolved of its implications. The vile treatment that was doled out to Turing and many other thousands of homosexuals who did not make it into the national treasury should remain as hateful, intolerant and horrific as it was in 1952.
We can only hope to do better by people in the present. Acting like we have the right to undo past wrongs, apologise for historic injustice or pardon those crushed by vile governments of old is only a self-serving exercise in historical denial. It is our responsibility to digest our history as it is and we should stand in the way of any attempt to tint it with a rosy hue.