Tantra [including sex and erotic elements] was developed during the middle [~500 AD] of the first millenium AD.
Thus tantric practices that are supposedly "associated" with Buddhism cannot be an essential and fundamental part of Buddhism proper.Tantra (/ˈtʌntrə, ˈtæn-/; Sanskrit: तन्त्र, literally "loom, weave, system") denotes the esoteric traditions of Hinduism and Buddhism that co-developed most likely about the middle of 1st millennium AD.
Starting in the early centuries of common era, newly revealed Tantras centering on Vishnu, Shiva or Shakti emerged. In Buddhism, the Vajrayana tradition is known for its extensive tantra ideas and practices.
This OP, Buddhism: "Enlightenment" through Sexual Orgies!
is a falsehood.
It is typical with believers of certain religions who had very low self-esteem to gain arrogance and false superiority by condemning other religions without any true supporting evidences.
Note the perspective of Tantra, Sex and Eroticism
One of the weakness of Tantra are the following features, i.e.The Tantra texts and tantric practices involve a wide range of topics, mostly focused on spiritual topics, and not of sexual nature.
However, states Gavin Flood, Tantrism is more known in the West as being notorious for its antinomian elements, stereotypically portrayed as a practice that is esoteric eroticism and ritualized sex in the name of religion, one imbued with alcohol and offering of meat to fierce deities.
[Nevertheless] Sexuality has been a part of Tantric practices, sexual fluids have been viewed as "power substances" and used ritualistically.
In most Hindu and Buddhist Tantra texts, extreme forms of sexual ritualism is absent. In Jain tantric text, this is entirely absent.
This is where SOME perverts will exploit the vulnerable followers.Need for initiation, esotericism and secrecy
Importance of a teacher (guru, acharya)