I believe there is an important line between a "loving" warning given gently and sincerely and a "loving" warning given from a sense of superiority and condescension to "save" someone. However, I also think losing the sense of concern that motivates a warning is worse than the warning itself. If we ever get to the point where we truly don't care enough to warn someone we love when we believe they are hurting themselves . . .
To be clear, some of the most obnoxious, hurtful statements I've ever heard have been given by people who did so thinking they were correcting out of love. I also understand that the most loving thing I can do in certain situations is to shut up - after it's been made clear that the other person doesn't share my view of the danger. That's one of my points - that once a "warning" has been given and understood clearly, generally it's up to us to honor agency and stop warning.
For example, if someone says, "I don't want to be contacted by Home Teachers or the Church," we should honor that and stop contacting them. Ironically, that is HT in the truest sense - providing the service the individual wants. I have no problem with an annual "check up" phone call or note ("Do you still want no contact?"), but anything more is moving from a warning voice to a constant and alienating telemarketing call.