One only has to look at how the UK political landscape has shifted from the massive campaigns around the abolition of an offensive but essentially toothless piece of legislation preventing "the promotion of homosexuality as a pretended family relationship" to being broadly accepting of the logic of gay marriage in less than a decade (interestingly that shift of opinion includes the British Prime Minister). Perhaps it's the benefit of hindsight making the dire warnings of the Right look ridiculous, perhaps the change would have happened regardless of decisions the legislature took in 2003, but either way it's difficult to dismiss the effect of legislative changes that don't make the sky fall in on people's attitudes.

I don't think many people in the UK think "what they did to Turing is OK"; the wider issue is whether a specific pardon is the appropriate response, not least because a pardon implies the recipient is exceptional in deserving it.

While 'toothless' it did have effects:

> As it did not create a criminal offence, no prosecution was ever brought under this provision, but its existence caused many groups to close or limit their activities or self-censor. For example, a number of lesbian, gay and bisexual student support groups in schools and colleges across Britain were closed owing to fears by council legal staff that they could breach the Act.

...even though it was mostly not applicable to teachers.