Which part therein?
Those are all some serious charges, which one(s) are true though?
All
1) Is a blind leader of the blind.
+Sanborn denies Church teaching on EENS, he holds the heresy that non-Catholics can be saved. He is blind and he teaches those who attend his sect this heresy, and they follow him
2) Has established a new church.
See above. What +Sanborn professes and teaches is not of the Church. His group is his own, with its own doctrine that must be held to be a "member"
3) Refuses sacraments to any Catholic that is not vetted as bending to his personal creed.
4) Is bizarre that he will refuse sacraments to any Catholic that actually believes the dogmas that...etc.
+Sanborn and his group refuse the sacraments to those who do not hold his opinions (some which are heretical).
5) His theology corrupts the very nature of the Church.
That is what heresy does. When you deny a Dogma, which is to be believed as a "truth fallen from heaven", you relegate the Church and Her infallible teachings to a mere human institution that you can decide to accept or reject at will. When you deny a Dogma of the Faith, your motive of faith is your own private judgement..not because the Church, who is the guardian of the deposit of faith, teaches it as Divinely revealed
6) He has become his own Pope
+Sanborn teaches his opinions as infallible, and attempts to bind the consciences of others with them . I'll admit, "false pope" or "anti-pope" would be a bit more accurate here