She was likely more uncomfortable with the talk about spirituality. That pushes the boundaries of business related discussion. Religion and business do not mix.

As for speaking about mental illness I think that would have to do with the nature of the talk and how that applied to business. For example, I have talked about Mental Illness in the workplace to businesses. My talks tend to be about establishing policies and standards regarding recognizing MI as a valid reason for leave, EAPs, etc.