Wrong again. The case involved a claim under RFRA (Religious Freedom Restoration Act). The Court did not at any time in the decision determine "importation of a controlled substance constituted a
legitimate religious practice."
It concluded the US government had failed to prove it had a compelling interest to stop the practice.
It can only be a legitimate practice if the government has no compelling interest to control it.
Nope! First, "legitimacy" is not, as I have said before, something the Court determines. Second, whether the government has a "compelling interest" is unrelated to whether there is a religious belief/religious practice.
Furthermore, there is a very brief line in the opinion in which the government conceded the "sincerity" of the religious belief/practice, not its "legitimacy, but its sincerity. I previously stated, the Court and courts can inquire as to whether the religious belief/practice is a "sincerely held religious" belief/practice. In the case you cited, the government
conceded the religious belief/religious conduct was "sincere," so the Court didn't even have to address whether the the religious belief/religious practice was a "sincerely" held belief/practice by the people/entity.
So, no, the Court never determined the "legitimacy" of any religious belief or practice in this decision. Ever!