My thoughts... I don't think what they did is blaspheme in a Biblical sense. Heres why.
Don't we all deny the Holy Spirit the moment we were born? To deny the Holy Spirit is to not be a Christian. Isn't that how all of the unbelievers are? It is our choice to accept Christ or not. What I see on the videos is just people saying they do not accept Christ at this time.
I think that is pretty much how all of us were before we became a Christian.
From a little research I found a reference to blaspheme in the Bible and it sounds like blaspheme is actually saying Jesus did his miracles through the power of the devil.
I didn't see where they said that in the videos
This site says it better then I can
Jesus warned the Pharisees that blasphemy against the Holy Spirit was unpardonable both in this age and in the next (Mt 12:32; Mk 3:29-30) in response to their insistence that he exorcised demons by being in league with Satan (Beelzebub). By denying that the Holy Spirit was the power behind the exorcism, attributing that power to Satan, the Pharisees spoke against the Holy Spirit. On this basis, theologians have commonly understood blasphemy of the Holy Spirit to be “attributing the work of the Holy Spirit to Satan or other demonic forces.”
Even this definition, however, needs refining. In responding to the Pharisees, Jesus also made the point that the work he did was obviously from the Holy Spirit (according to the logic of his argument in Matt. 12:25-29 and Mark 3:23-27). There was no reasonable explanation for the exorcism other than the power of the Holy Spirit, and this should have been evident to all. The Pharisees rejection of the Holy Spirit was thus informed and willful; they had not simply made a mistake. Speaking from the evil of their hearts (Matt. 12:34-35), they had intentionally blasphemed what they knew to be the power of the Holy Spirit.
Blasphemy against the Holy Spirit is informed and intentional, motivated by evil. Because it is unforgivable, it cannot be committed by a Christian, or even by someone who is not yet a Christian but who later will come to faith. A college professor, who, while knowing the truth about God, dedicates his career to turning away young adults from the Christian worldview, would be a modern example.
Even so, sincere Christians sometimes fear that they, in an unguarded moment, have blasphemed the Holy Spirit. Usually, these people have simply misunderstood the nature of such blasphemy, or have misjudged their own actions. In any event, since the reprobate (those who will never come to faith) cannot feel true remorse for their sin (cf. Acts 11:18), Christians who fear that they may have committed this unpardonable sin generally show by their very anxiety and remorse that they have not done so.
source http://www.thirdmill.org/files/english/html/th/TH.h.Mclaughlin.blasphemy.holy.spirit.html