What am I missing? What are the priors for trusting the author of this blog more than the seemingly universal voice of these authorities?
There's a number of physicians who are worried about the way modern physics operates and particularly about string theory. Peter Woidt is an influencial voice in this debate and has written a book about it, but he's far from alone. The criticism is that string theory has failed in a lot of the things it was supposed to solve, that the LHC hasn't supported the idea of supersymmetry particles, which was a key concept within string theory and was expected by its proponents. Also a key criticism seems to be that there's no real reason to believe string theory is true and other attempts are false, but there seems to be a strong opinion by many string theorists that alternatives should not be explored.
Admittedly I have mostly read one side of this debate.
But you don't really have to worry about the distinction here. Woit is not advocating for any of the alternative approaches to quantum gravity. He's aware that they are basically crap. His complaint is that he thinks the string theorists are claiming to have solved the problem.
Certainly one shouldn't believe everything an expert says uncritically, and anyone is entitled to investigate even the most authoritative pronouncement, but I think believing that pure reason, without the benefit of specialist training, is the equal if not the better of expertise and experience can lead one all too quickly down the wrong path.
(For example, pure reason definitely rebels at first against quantum mechanics--at least, mine does, and I'm a mathematician!)
Of course if the authority has critical information that can not be communicated then no compelling argument can be made and the age of enlightenment was but an illusion.