It's not about having an open mind about Superstar. It's about allowing G-d to move in the way He prefers without forcing Him into a box.
Half the time we think we are defending Him we are really defending ourselves. It helps to remember that He doesn't need to be protected by us or from us.
IMHO the dividing line should be this:
If someone is presenting someone who is clearly anti-G-d (Jesus was not G-d in flesh, Jesus was not resurrected, G-d is part of the universe, not its creator, etc.) then you are obliged to stand up for the truth.
If someone is presenting someone who is very similar to G-d but a little off, let him go if he is clearly interested in knowing G-d. You may be the one who is off. G-d is in the business of correcting His children and He will reach out to anyone who is dilligently seeking Him, no matter how mistaken they may be in their understanding of who He is.
Always remember that G-d is infinite and we are finite. Therefore any notion we have of Him will always be wrong - if only in that it will be incomplete for all eternity.
Shalom.