I don't know if Woit explained it, but there are multiple attempts at explanation by other people who have been pointing out the self-serving nature of string theory publicity. Lee Smolin's "The Trouble With Physics" mentions access to funding and the absence of experimental pressure to divulge of unproductive theories: by dint of the hype in the 80s and 90s, many theoretical physics departments were staffed mainly with string theorists. This means that if you want to earn money doing theoretical physics, there are many people who won't complain too loudly if you choose string theory, and many people advising grants be written for string theory research. Other fundamental theories don't have this lobby, not because they are in any measurable way more wrong than string theory, but by historical happenstance and perhaps pure mathematical sexiness (as opposed to actual physical reasons). Usually, in a natural science, we can fall back on empirical data to correct such "intellectually nepotistic" networks that all humans are wont to fall into, but since the standard model is so frigging successful, this is missing.

But no matter the actual reason, I think anyone with a post-graduate science education can agree that it's a pretty big howler to call string theory an A+++ physical theory, when it so far hasn't predicted a single thing. That's a clear sign that the people talking are engaged in empty PR, not in informing the public in any meaningful way.