seriously, that's the answer.
preachers preach. They don't have to be
right, they just have to be loud and make the hearer feel the way the hearer thinks they should.
scientists strive to be
right and to not lie, embellish or belittle.
preachers on the other hand feed off of and feed to emotion.
IDiots are often either preachers, or are preaching. They learn and know how to speak - plus it's a lot easier to say "I know this" when it's from ancient books written by goatherders purportedly saying what an omniscient, omnipotent and omnipresent deity can or can't do, than when talking about apparent laws discovered by hand from within the system itself.
Scientists often don't know how to speak to the public either (see thunderf00t's meeting with the bananaman for making that cringingly clear).
When a scientist CAN speak - see PZ Myers, Richard Dawkins, Carl Sagan and many more - then they are beyond intimidating for IDiots because they show them up on their "home turf".
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