Complex sentence: It would not be appropriate to give undue weight to the physicists, but I believe JJ is going to the opposite extreme, trying to dismiss the physicists as pseudoscience, and give them zero positive weight.
Split into simpler sentences: It would not be appropriate to give undue weight to the physicists. But I believe JJ is going to the opposite extreme, trying to dismiss the physicists as pseudoscience, and give them zero positive weight.