Yes, people in the LGBTQ community have been, and continue to be, targeted unfairly and accused of "crimes" they never committed. The idea of pardoning people who were inaccurately and unjustly convicted of offenses is correct, even if it is being done posthumously. It is never too late to try to right a wrong. All nations should be encouraged to do so.
This is a positive step forward, but it is only one step. There is a lot more that needs to be done to make amends, and honestly not all of these things can truly be made up for. Alan Turing's story is ultimately really really sad, and it could have been prevented.
Yes, more nations should adopt a similar law because it is unfair for gay men to be charged with some kind of criminal activity simply for being gay. It is inhumane, and more laws should recognize this. Gay people should be allowed to express who they are without fear of retribution.
Pardoning gay men of historic offences does not change the fact that these men suffered terrible abuses at the hands of the state in the past and nor does it change the fact that gay men and women still face considerable discrimination in the twenty first century. A greater tribute to men like Alan Turing would be to ensure that no one is discriminated against for their sexuality ever again.