Yes when the Dalai Lama says this, He is literally putting the whole Guru Tree down and in retrospect the Dalai Lama was saying He is also wrong because everything He was taught came from His Gurus. We cannot be selective and say the Guru was right about this subject but wrong about the other one, in Vajrayana Buddhism, the concept on relying upon one's Guru and the "samaya" relation with one's Guru is huge and sacred, it's not like a normal Guru that teaches us in our secular world, we're talking about fully attained/enlightened masters who have achieved Bodhicitta. So in fact HHDL has severed His samaya with His Guru whom he publicly announced that is wrong. This means all the teachings HH received are false and would have no effect and if that is the case, the Dalai Lama should not be giving any teachings to anyone and should refrain from giving empowerments, because it is false and there will not be any blessings from the lineage masters due to broken samaya. This is very dangerous as we all know it can put teacher and student's life and practice at jeopardy.
Yes this is a huge joke since day one of Him saying this and this is a fact because if HH was not just making it up, then why would He wish to invite HH Trijang Choktrul Rinpoche to the Lamrim teachings and why would He even allowed HH Trijang Rinpoche to practice Dorje Shugden and only Trijang RInpoche is only allowed? That is all a bunch of baloney and those in Dharma will all know and those who don't know the Dharma like the common Tibetan folks. This goes to show many Tibetans have know real knowledge of Dharma... in this way Buddhism is dragged down and destroyed from common superstitious beliefs instead from real evidence and knowledge.