Distinguish fish eyes from genuine pearls: The essence of Buddha dharma is the eight vijnanas, not six vijnanas
In the teachings of Buddhism, it's allowed to distinguish the fish eyes from the genuine pearls. It means the Buddha dharma have to be kept purely. It means the essence of Buddha dharma is the eight vijnanas（八識論）. If there is one sect insisting the characters of all dharmas are consciousness (the 6th vijnana), it's far away from the teachings of Buddha Shakyamuni, and has to be pointed out as a fake one because the consciousness vanishes every night and it is impermanent which is not the Diamond Heart to be meant.
Unfortunately, the lamas of Tibetan Buddhism teach their followers that the consciousness (the 6th vijnana) is the core of Buddhist teachings and they can experience the enlightenment during tantric sexual practice. Therefore it's important to point out their fake teachings. Because the Buddha Shakyamuni never teaches the tantric sex. Because the Buddha Shakyamuni always says the consciousness is impermanent and dual. The consciousness is definitely not the Diamond Heart.
If you are really interested in the Buddhist teachings, please read some teachings of Four āgama Sutra（四阿含經）about the teachings that the consciousness is not the target of true dharma.