I agreed on the important of lineage. Lineage is the guarantee authenticity of teachings. Lineage is a sacred trust through which the integrity of Buddha's teachings is preserved intact as it is transmitted from one generation to the next. The important link through which the spiritual tradition is maintained is the profound connection between an enlightened master and perfectly devoted disciple.
Kyabje Trijang Rinpoche is the junior tutor of the 14th Dalai Lama. If Trijang Rinpoche can be wrong on the practice of Dorje Shugden, then other teachings from Trijang Rinpoche can be wrong too. Dalai Lama might have received wrong teachings from Trijang Rinpoche. This is very scary. If these wrong teachings continue to spread and all of us will not be able to attain enlightenment. We will stuck in samsara forever.
If Dorje Shugden is a spirit, whoever that practice Dorje Shugden should end up in the lower realms. But Trijang Rinpoche and many highly attained that practice Dorje Shugden has reincarnated back to benefit others. Can Dorje Sugden be a spirit? It does not make sense right?