Mark 3:28 , again Jesus teaching, " ALL sins and blasphemies shall be forgiven men." All of them, in 1 John 3:5 Jesus took all sin away, no Christian can bring any of them back and try to condemn someone.
It says in 1 John 3:5 that Jesus came to do away with sin. Then it says that he who continues to sin is a child of the devil. If there was no such thing as sin, how can anyone continue to be a sinner? As 1John 3:4 says, sin is disobedience to the law. The only way that Jesus did away with sin is by teaching the right way to understand and comply with the law that leads to eternal life. If you do not do it, you cannot have the life promised for obedience to the law in you and are not saved from the consequences for failure to comply with the will of God..
Now this so called " unforgivable sin", sinning against the Holy Spirit, there are exactly zero example of just how to do that given in scripture; so in my view, its impossible for a person to do it.
Your just going to have to find another way to condemn.
Jesus didn't seem to mind people calling him crazy, a drunk, a liar, whatever. What he said was unforgivable was people saying that the source of his inspiration, God, was evil.
I'm not trying to condemn anyone. According to Jesus to deride a revelation of truth from God as evil can never be forgiven.