1 Corinthians 14:38: "But if any man know not, he shall not be known"
2 Saint John 1:9: "Whosoever revolteth, and continueth not in the doctrine of Christ, hath not God. He that continueth in the doctrine, the same hath both the Father and the Son."
Heresy was always false, but not necessarily always heresy
But Mike does not acknowledge with St. Augustine that Catholics who err materially on points not contained in the Creed, so long as this is not done out of malice or with the will to oppose the Church, are not counted guilty of the sin of heresy (though such people are nevertheless to be reproved - and if they deny the need to change their opinions, then they ARE heretics).
And his only response was "Nice try Jew". No rebuttal, no refutation. No reasoning at all of any kind. He basically said: "Na na na na naaa naaa, I can't heeear yooou!" Rather than answering our arguments, he said that people should just block email from us. Never mind that he can't answer.
And as has been mentioned before, there are dogmas that Mike does not profess on his website; they are conspicuously missing. Mike does not teach the dogma that the Baptism of John is inferior to that of Christ (Trent, Session 7, Canons on Baptism, Canon 1), nor the dogma that Christ and the apostles had possessions truly their own (Pope John XII, Quum inter nonnullos).
By not teaching these dogmas he is failing at his own made up religion!