Most of these are half truths, or not even true.
If a person who have been dedicated in this reincarnation, and they decides to leave Satan, most probably, the way they will leave is to stop meditating. If not they will start practicing craps of new age.
If a person is not confident in Satan to be "good" or to be our real God, but they will start to practice the beginner meditations anyways, as they see no harms in them, than it is totally okay, and maybe that will be key for them to start to believe.
Not everyone has a Guardian, but only dedicated Satanists. This is probably our biggest gift that comes with dedication.
Beginner meditations on JoS can be practiced by anyone. Whatsoever they should be aware that these are gifts from our Gods