re: Can you hear me now?
What you say is most likely true, but who knows what really advanced cultures might be up to? They may delliberately blow up stars in order to generate tame black holes. Even though their technology may be extremely energy efficient, they may also do some pretty cataclysmic stuff for specific goals. Every technology must have a fringe of super-projects that they haven't completely optimized yet.
Actually, astronomers are very interested in astrophysical phenomena they can't explain as a result of natural processes, for this very reason. Alas, they haven't found any likely suspects yet.