Even if Lex ignored the fact that the Midnight Inn was literally training its workers inside the Temple of Fasting, which was a temple specifically made to train humans, and contained the heritage of all thirteen of the first humans, his presence alone would be enough to get them pulled into this war.
If the enemies of humanity, whoever they were, operated with the agenda to eliminate anyone with immense potential, then Lex would be at the top of that list if they ever discovered him. No wait, if any Jeffrey clones survived, and had the memories of him from back in the Trial of Eternity, then Lex should operate under the premise that news of his potential had already spread, or was eventually going to be spread.
After all, that's what Lex would do if he had an enemy he couldn't kill himself. He would make sure that anyone who might seek to harm his enemy would be equipped with the most accurate, up to date knowledge.
