There are always the real followers and the false followers. This happened to the christians as well. Or even in Chaitanya Lila the followers of Adwaita Acharya deviated from the standard given by the previous Acharyas and were thus rendere...d useless... Every morning the devotees sing, that without the mercy of teh Spiritual Master you can not make any advancement. And this is why ISKCON failed so badly.
They offended Srila Prabhupada and thus lost his mercy and self realization became impossible for them. In conditioned state, we can come illusioned. That's why we NEED THE MERCY OF A SELF-REALIZED PURE DEVOTEE! But if you offend your Guru and usurp the people who are attracted by him, you spiritual life is immediately finished.
No matter what ISKCON says it is all useless, because nobody there is self-realized! Prabhupada wanted all of his disciples to become fully self-realized.... But so many Offenses happened and most ISKCON devotees could not move past the ANartha Nivritti stage. That's why the ISKCON "Gurus" fall down all the time. Srila Prabhupada warned about this many times. "As for your next question, can only a few pure devotees deliver others, anyone, if he is a pure devotee he can deliver others, he can become spiritual master. But unless he on that platform he should not attempt it. Then both of them will to go to hell, like blind men leading the blind." [Vedabase 2003 - Letter to: Tusta Krsna - Ahmedabad 14 December, 1972 72-12-14]
It is actually very sad what happened there. Prabhupada wanted to deliver all of his disciples, but Maya caught them in her trap. All these devotees were trying to serve, but the illusion was so strong that they commited offense and are on their way to hell. This is a sad occurance. May we hope for the well being of all devotees. Robin