Interesting happenings in Tibet. I do believe that Kyabje Pabongka Rinpoche spoke against mixing of Gelug teachings with Nyingma teachings. He probably used quite a harsh tone to drive home this point. His point was to emphasize loyalty to one's lineage and Guru and its intent was not sectarian. However, knowing the Tibetans students of varying dispositions and capacities, they probably misconstrue the meaning and took it out of context.
Hence, some misguided students of Kyabje Pabongka Rinpoche probably acted waywardly by destroying Guru Rinpoche statues and places of worship. However, I am very sure Kyabje Pabongka Rinpoche probably never condoned such acts as Guru Rinpoche is a previous manifestation of Lama Tsongkhapa and hence a Buddha. How can he be who he is and condone that? However, the forced conversion of monasteries and temples was carried out by certain government regimes like that of the earlier Fifth Dalai Lama towards certain Kagyu and Nyingma monasteries did occur. Scholars attribute it to placate the powerful patrons of these monasteries who were threatening the Gelug at that time.
I agree totally with Big Uncle. It is probably some over enthusiastic students of Pabongka Rinpoche who did that if at all. Or it could be some over enthusiastic students of Chagdud Tulku and Jamyang Khyentse Chokyi Lodro??!!
Anyhow, we are living in a degenerate age and we have the karma to see all this happens. All this events are also as real as we chose to see them. Each Lama has their methods that addresses their own diciples but others take it out of contexts.