This is technically an exercise of the Royal Prerogative of Mercy, which the Queen exercises on the advice of the Lord Chancellor/Justice Secretary - in this case Chris Grayling.
Turing's pardon is exceptional, as the Queen has only pardoned people who have been found innocent after they have been sentenced - and in two cases, these have been posthumously after the death penalty. Turing was never found innocent - although what he was sentenced for is no longer on the statute books.
This is one aspect of the justice system - you can be found guilty, and your only hope is mercy. And it is a Royal Prerogative - up to the Queen ultimately to grant or not to grant. You can't make her, you can't force her hand.
The Bible tells us that we have all fallen short of God's standards:
But now the righteousness of God has been manifested apart from the law, although the Law and the Prophets bear witness to it — the righteousness of God through faith in Jesus Christ for all who believe. For there is no distinction: for all have sinned and fall short of the glory of God, and are justified by His Grace as a gift, through the redemption that is in Christ Jesus, whom God put forward as a propitiation by His blood, to be received by faith. This was to show God's righteousness, because in His divine forbearance He had passed over former sins. It was to show His righteousness at the present time, so that He might be just and the justifier of the one who has faith in Jesus. (Rom. 3:21-26)
The solution God has provided is a simple one - His exercise of the Royal Prerogative of Mercy. It is up to Him to decide whom he shows mercy to. We can't demand it.
My little children, I am writing these things to you so that you may not sin. But if anyone does sin, we have an advocate with the Father, Jesus Christ the righteous. He is the propitiation for our sins, and not for ours only but also for the sins of the whole world. (1 John 2:1-2)
Who is to condemn? Christ Jesus is the one who died — more than that, who was raised — who is at the right hand of God, who indeed is interceding for us. (Rom. 8:34)
Now, you could argue that fair enough, Jesus is Heaven's Justice Secretary - albeit one who takes the punishment for us, which is not what Grayling ever does - but that God the Father could turn round and say "no". Or that we cannot be sure if Jesus will ask for the Royal Prerogative of Mercy to be exercised on our behalf.
Jesus Himself assures us:
The Father judges no one, but has given all judgment to the Son, that all may honour the Son, just as they honour the Father. Whoever does not honour the Son does not honour the Father who sent Him. Truly, truly, I say to you, whoever hears My word and believes Him who sent Me has eternal life. He does not come into judgment, but has passed from death to life. (John 5:22-24)
So, judgment is entrusted to Jesus, and this is His criterion for deciding whether we have eternal life or not - whether we believe Him or not.
We are assured that:
There is therefore now no condemnation for those who are in Christ Jesus. (Rom. 8:1)
While tomorrow the focus will be on the baby Jesus, remember why He was born. Remember that a third of a century later He was crucified for our sins.