Skepticism is a great thing. The world needs more of it. Imagine how much better off we'd be if more people questioned religion, astrology, holistic medicine, the motives of government and business, etc.
However, questioning should be done with respect. Well, at least a sliding scale of respect. For example, beliefs or opinions without evidence or even a good chance of being true can be challenged with very little respect. Views backed by observation and agreed upon by 93% of climate scientists, the experts in this field, should carry more weight.