As much as you dislike the government, you can't just ignore how incredibly powerful it is in people's daily lives. The incidents of legally recognized marriage are very real and very significant. I've met many families separated (or threatened with separation) by immigration law that didn't recognize same-sex couples. No amount of saying "fuck off" to the government is going to change whether you're family members will be allowed to live in the same country as you.
In the case of Alan Turing, no amount of him saying "fuck off" to the government could prevent them from criminalizing his relationship and chemically castrating him. The UK government issuing a pardon is a overdue recognition that they instituted a campaign on suffering on many people, one of whom hand a significant part in saving the country from the Nazis.