I've only watched this debate from a lay person's view (no physics background and thus I have no chance of understanding what these theories are about), but fro

I've only watched this debate from a lay person's view (no physics background and thus I have no chance of understanding what these theories are about), but from what I understand: 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.