Exactly false. People could have looked the other way, and Turing could have lived a longer, happier life, and we could all be that much less aware of the injustice done to hundreds of thousands of other LGBT people throughout the last century. The tragedy is the policy that cost Turing his life, not the fact that an exception wasn't made for him. It cost many more people than Turing.
Yes, wow. To go further, there is something deeply troubling about the parent's line of reasoning: that the tip of its spear is that Turing could have helped computing more, and not that the law was heinous in its treatment of humanity. The priorities required to even think of a point like that baffle me.