Answer
It is not that all conclusions are wrong — many conclusions may be right. But there is one fundamental difference, and that difference is very significant.
The issue is this: the idea that someone can become a guru without proper authorization, and that such persons are then presented to the world as spiritual masters — “Come, surrender to them, they will take you back to Godhead.” This is where the real divergence lies.
Our understanding is different: that Śrīla Prabhupāda is the one who can deliver us back to Godhead. So while it may appear to be just one point of difference, it is actually a very major one. It cannot be minimized by saying, “Oh, it is only one difference,” because that one point determines the ultimate goal — whether one truly goes back to Godhead or not. And that is the very purpose behind all the other instructions.
So even if there are many similarities, this central issue carries the greatest weight.
At the same time, we should also be introspective and humble. In the past, we too may have placed our faith in someone who was not actually a bona fide spiritual master. Recognizing that helps us remain grounded and avoid harsh judgment toward others.