Unfortunately, some Buddhists as well as others of different faiths tend to condemn Vajrayana openly for its need to keep certain views secret. This is not right. Even non-tantric Mahayana upholds confidentiality in the doctrine of emptiness. Does it mean the doctrine is flawed? Of course not. The Buddha promulgated his teachings in order to deliver sentient beings from all suffering, not to flaunt his own importance or unsurpassed wisdom, irrespective of the suitable time, place, and audience. So an orderly transmission of the Dharma is of particular importance in Buddhism.

~Depicted from GATEWAY TO VAJRAYANA PATH - A Compendium of the Vajrayana