I am not sure why would someone advice anyone whether to repeat a particular mantra or not to repeat it. It is a very personal matter. The mantra should either spring up from within or else it should be given by a guru who has undertaken the responsibility of the disciple.
But if it is a question of general principle then it is true that a mantra that helps someone might not be of help to another person. However to specifically advice not to use this mantra or for that matter any other mantra does raise questions on the force that is driving the person. One can offer one’s point of view but to advice someone not to do a mantra that one may be doing, especially the mantra OM Namo Bhagavate doesn’t sound good.
Affectionately,
Alok Da
