What we should be pushing for is a redaction, and an acknowledgement that the prosecutors were ignorant morons who harassed and extinguished a great mind because they didn't know any better.
In this case, I guess pardon is not appropriate. I think the way we think of pardons at least in the US, is your first sentence, in which case Turing should definitely be pardoned.
Although rare these days there were times when a pardon could be won or purchased in exchange for services rendered. It didn't mean that you were innocent of your crime.
The prosecutors, judge J. Fraser Harrison for example, appear to have been far from moronic.
An unambiguous cause for Turing's suicide doesn't appear to be known.
Your allegations of ignorance though seem valid.