JW's know that Matthew 12:32 shows that there is only one unforgivable sin - sinning against the holy spirit. Also that the scriptures reveal all judging is to be done by Christ Jesus - John 5:28,29; Acts 10:42 &17:31, Romans 14:9; 2 Cor. 5:10; 2 Tim. 4:1; 1 Pet. 4:5; Rev. 11:18; & Rev. 20:12.
Implicitly, JW's are doing Jesus' judging for him, by saying that all the billions on earth who refuse to join their religious denomination must have committed the unforgivable sin, and therefore will be destroyed forever at Armageddon! Why did Jesus et al forget to mention this little point about membership of the WTBTS?