You seem to have a severe inability of thinking clearly and reasoning. Just because you can quote someone saying “Buddhist tantra is not really buddhism” this doesn’t mean that this is something meaningful that should be taken seriously. Assertions are 100% meaningless without reasoning. Did you notice there is a total absence of reasoning in your quotes?
You say these practitioners are having sex, who cares? Even 'Buddhhism’s own quotes say that these are not sex activities of ignorant people driven by lust and desire:
“Actually, […] the sexual organ is utilized, but the energy movement which is taking place is, in the end, fully controlled. The energy should never be let out. This energy must be controlled and eventually returned to other parts of the body. And here we can see there is a kind of special connection with celibacy.” - Quoted from “The Good Heart,” H.H. the Dalai Lama
“Although I am using this ordinary term, sexual climax, it does not imply the ordinary sexual act. The reference here is to the experience of entering into union with a consort of the opposite sex, by means of which the elements at the crown are melted, and through the power of Meditation the process is also reversed. A prerequisite of such a practice is that you should be able to protect yourself from the fault of seminal emission. According to the explanation of the Kalachakra Tantra in particular, such emission is said to be very damaging to your practice. Therefore, because you should not experience emission even in dreams, the tantras describe different techniques for overcoming this fault.” - The 14th Dalai Lama
And these are not even precise or detailed explanations. As for ‘Buddhism’ i already dismantled his assertions in a previous post. I showed that contrary to his assertion that gelug lineage is not authentic because it accepts consort practice, it is authentic, since consort practice is done by only 1 in 10,000,000 practitioners and it is irrelevant for everyone else. Instead of being something common, as was her assertion, it is utterly rare to the point of being irrelevant. Aside from those rare practitioners, everyone else is practicing standard madhyamaka and studying the tenet systems. You would have to argue that madhyamaka is not authentic in order to establish that gelug is not authentic. You cannot argue that gelug or tibetan buddhism is not authentic because they accept consort practice.
However these days not even theravadins are willing to make such arguments, many now even accept bardo beings and chi (energy winds) that are explained in tantra. Do you really think mental movements do not have subtle physical signatures findable in the body? That is all energy winds and tantra are about, how to use them, instead of only relying on samadhi. (You need both)
There is no such thing as tibetan tantrism and lamaism. The lineages derive directly out of india, they are the exact same lineage, just as tibetan buddhism will eventually find root in the west, it will not become “western buddhism” it is simply a continuation of the lineage. Very many indian yogis wrote amazing commentaries on tantric texts long before tibetans ever heard of buddhism.