Yes, the point you make has some gravity, though the issue is not one of sin, per se, but of perpetuation in lies and dishonesty and critically, performing these things under the guise of Jehovah’s name. It is true that we are all guilty of sin, but if you compare the issues of sin comparatively with the words of Jesus to the Pharisees, the criticism and much of the reasonable anger rests upon the same rock of contention - and that is one of lies, pride, abuses of and to the flock and a multitude of other issues such as meddling with the meaning of truth, self aggrandisement, greed, avarice, involvement with the world in commerce and financial gain and fraternising with evil intent for gain, e.g., their dalliance with investments in nefarious companies, harming the brethren for gain (vaccines and selling of their property dedicated to Jehovah) and worse, perverting Jehovah’s truth for gain through paying fines for child sexual abuse with money that was dedicated to the furtherance of the truth - and so the list goes on. There is no excuse, acknowledgement or repentance from them and hence the justification for retort.
Compare what Jesus said to the Pharisees “ You are from your father, the devil …”and what he said to the woman caught in adultery and about to be stoned to death. First to the crowd (and as you so rightly point out) “Let you who is without sin, cast the first stone…” and turning to the woman, said, “Who accuses you? (after the crowd had dispersed)…then neither do I.…”, then the critical issue of value in judgement. “ Go your way and sin no more.” Thus harsh criticism has its place to alert others, and then tempered with mercy when there is a point to be gained, is also used at the appropriate juncture for a witness to the truth. The problem with the Governing body though is that they have already been told and the telling has been done with humility. Yet all was rejected and not only rejected, but over the years sins have been added to over and again. They did not “sin no more” but continued in and added to their sins. Thus in analysis of your justifiable and welcome comment, who does the GB mimic? The crowd ready to kill another for their sin, or the woman, who chastised, sent on her way in repentance and told to sin no more?
I have yet to meet anyone on this site who does not recognise their own vulnerability to sinning, and to their awareness of being “unworthy” of any consideration before Jehovah, hence, “miserable man that I am for what I should do, I do not do…” but is that the point in criticism of the GB? I do not think so. It is the watchtower’s continuance of their transgression in the face of rebuke that is in contention here, just as Jesus said to the Pharisees - it is not said without due reason. Are we not commanded to hate evil? To speak out against it? To warn the flock? In recognition of such, Jehovah says that His inspection of this earth’s inhabitants will begin in His own House. Thus if evil is rife in His own House, how can we ignore it? It is fact. Gratuitous mockery is unnecessary I suppose, but even that is evident amongst Jehovah’s own people with their fickle tendency to take a piece out of another over imperfections. But how does one compare that with shunning and the heartless, unreasoned treatment sanctioned by watchtower through their abusive and thoughtless application of misunderstood analysis of scripture? Yes, Jehovah has provided watchtower, but for those not introduced to the truth via watchtower, do you think Jehovah will not provide for them, or that in their lack of understanding, but righteous heart, that Jehovah will neglect them? The watchtower is hardly the only means of gathering such together. All those who “hear” the words of Jesus and recognise his voice will be subject just as much as those within the watchtower to mercy in their judgement by Jehovah. I dare say that everyone here has truth in their heart, though perhaps, like me, it is not greatly described in knowledge, - rather than their head where without its component part of love, is worth nothing. Likewise for the “great crowd which no one can number”.