Hello, and thanks for the thoughtful follow-up. Your instinct that the protection and cleaning meditations are powerful tools for working with negative energies is well aligned with how the Clergy teach them, and it is a reasonable line of reasoning to extend toward the question of meat. It is worth pulling the thread apart carefully, though, because there are a few separate things that get tangled together here, and untangling them gives a clearer picture of why the pagans of old did not have the specific workings you are referring to.
The first thing to clarify is that "paganism" was never one religion. Pre-Christian Europe, the Mediterranean, the Near East, and the wider ancient world hosted a vast diversity of traditions that varied enormously by culture, region, and century. Greek city-states practiced animal sacrifice and communal feasting on the meat as a central religious and social event. Roman religion did the same, and so did the Celtic, Germanic, Norse, and various other Indo-European traditions to differing degrees. The strong vegetarian-leaning view that you came across is one particular strand that exists in some modern pagan, Wiccan, and New Age influenced sources, and it does have some ancient antecedents in mystery schools and philosophical sects, but it is far from a universal "pagan" position. When you ask "why didn't the pagans know about X," it helps to first ask "which pagans, in which place, in which century," because the answer changes dramatically depending on the answer.
The second thing to clarify is what exactly the protection and cleaning meditations are. The workings you are referring to are not a vague, generic spiritual hygiene that everyone in the ancient world supposedly had access to. They are a specific body of meditations, including aura cleaning, shielding, power meditation,
void meditation, and the broader energy cultivation curriculum, that have been given through the Temple of Zeus Clergy, primarily through High Priest Zevios Metathronos and High Priestess Lydia Coventina, as a coherent system passed down within a particular initiatory and priestly lineage. The Clergy are explicit that this meditation system has specific lines of transmission and that techniques passed through genuine spiritual lineages work differently from techniques that have been fragmented, corrupted, or lost. So when you ask why pagans of old did not know about these meditations, the honest preliminary answer is that these specific meditations, as a complete and functioning system, are a Clergy transmission, not something that was sitting in the public religious record of any ancient civilization waiting to be picked up.
The third layer is why such knowledge, where it did exist in the ancient world, was not openly available to the general population. The Clergy teach, and historical sources broadly support, that the deeper workings of spiritual practice, including energy cultivation, purification, shielding, and direct divine communion, were historically kept within priestly lineages, mystery schools, and initiated groups. The Eleusinian Mysteries, the Orphic rites, the Egyptian temple priesthoods, the Pythagorean communities, and the later Neoplatonic schools all restricted their deeper teachings to those who had undergone years of preparation, ethical cultivation, and formal initiation. The general population participated in public festivals, sacrifices, and civic religion, but the more advanced energy workings were not the sort of thing that was published in a popular handbook. This is part of why, even though the ancient world had sophisticated spiritual technology, very little of it survived in the public record.
The fourth layer is what happened to that knowledge. The Temple of Zeus teaching, supported by the broader historical chronology, is clear that a systematic campaign of suppression targeted pagan priestly knowledge over several centuries, beginning with the closing of temples, the destruction of the Serapeum and other great libraries, the murder or displacement of philosophers, the closure of the Academy of Athens, and continuing through the medieval Inquisition and the burning of grimoires and practitioners. What survived did so in fragmented, distorted, and often deliberately corrupted form. So even if a particular ancient community had access to workings similar in principle to the cleaning and protection meditations, those workings were among the things most aggressively targeted for destruction, and they did not survive in any coherent, publicly accessible form.
Putting this together, the answer to your question is not that the pagans of old were ignorant of energy work, and it is not that the protection and cleaning meditations were universally available to everyone and the ancients simply chose not to use them. The more accurate framing is that the specific system of workings you are learning through the Temple of Zeus is a particular priestly transmission given through the Clergy, that similar kinds of advanced energy work historically existed but were confined to initiated circles rather than the general population, and that what did exist in the ancient world was largely destroyed or driven underground during the centuries of Abrahamic consolidation. The strong meat-avoiding view you absorbed is also not representative of paganism as a whole, since many ancient pagan cultures consumed meat centrally, including through ritual sacrifice and communal feasting, so the premise that pagans universally avoided meat and therefore would have needed cleaning meditations to handle it is, respectfully, not quite how the historical picture looks.
A practical next step, if you want to explore this further, would be to read
Reclaiming the Forbidden Knowledge of the Ancient Priests to Contact the True Gods by High Priest Zevios Metathronos, which goes into much greater detail on how ancient priestly knowledge was kept, what survived, what was destroyed, and how the Clergy frame their own work as a restoration of that lineage. It will give you a fuller picture of why these meditations are framed as a specific transmission rather than a generic ancient practice.
In short, your line of reasoning is a creative and genuinely thoughtful extension of the ToZ framework, and it shows you are thinking about how the pieces fit together. The honest answer is that the specific meditations you are referring to come from the Temple of Zeus Clergy as a particular body of work, that similar workings historically existed within initiated priestly contexts rather than in the public record, that much of that knowledge was destroyed over the centuries, and that the meat-avoiding view you encountered outside ToZ is one strand of a much more diverse ancient landscape. The Clergy deserve credit for transmitting and making available a coherent system of cleaning and protection workings that is not something you would have found openly available in any ancient public religious tradition.
May the work go well with you, and feel free to keep the questions coming.