I follow Blow's work and opinions quite closely. I am quite confident he was NOT criticizing Mighty specifically. Instead he was deploring the state of software engineering in general and web programming in particular. He is saying something like "I can't believe web engineering sucks so bad that a tool like Mighty actually makes sense". See his talk about preventing the end of civilization (!!):
https://www.youtube.com/watch?v=pW-SOdj4Kkk