This has nothing to do with purgatory. That is an idea you are bringing to the text.
Leaving aside what "speaking blesphemy against the Spirit" means, Christ says it will never be forgiven in this life or the next.
Paul writes in Corinthians that the works of believers - the saved - will be tested by fire. Obviously, to be a believer, you would have to be forgiven of all your sins. Failing that, you won't be rewarded for works. Ergo, these believers never blasphemed the Spirit.
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Do you have any evidence from before 100ad that supports your claims? If so, it would be great if you would share it here for us all to discuss.
"It is one thing to stand for pardon, another thing to attain to glory: it is one thing, when cast into prison, not to go out thence until one has paid the uttermost farthing; another thing at once to receive the wages of faith and courage. It is one thing, tortured by long suffering for sins, to be cleansed and long purged by fire; another to have purged all sins by suffering. It is one thing, in fine, to be in suspense till the sentence of God at the day of judgment; another to be at once crowned by the Lord."By way of context, Cyprian is making an apology for why he has chosen to allow the "lapsed" -- those who sacrificed to the Roman gods to save their lives during persecution -- back into the Church after they repented. He is maintaining that despite his willingness to welcome them back, the path of martyrdom is still better, because it is better to be purged of all sins via an earthly martyrdom than to have them purged by fire before we stand before God.