That axe sharp enough yet, Donut? We've been over this already. Her "allowing" Utsuho to destroy Gensokyo, as you put it, is kinda refuted by her challenging Utsuho to fight, twice, both before and after making her quip about an interview, and assisting Reimu on her quest to get to the bottom of the story. It seems highly unlikely that she was serious about the interview request in light of these two challenges, and in light of the fact that she lives in freakin' Gensokyo.