I hated the central plot point of the second book and I really don't understand how in the fuck they could keep it around instead of killing it with nuclear fire forever
Even if you ignore its inherent worth (and a major theme of the books is the inherent worth of things that don't look or think like you), it was still an amazing discovery with incredible potential. IMO it was less dangerous that the (admittedly much less innately terrifying) sympathetic aliens, who were capable of deep space travel, unpredictable, warlike, and also very difficult to communicate with.
(I was actually asking the opposite question by the end of the book - once it was convinced to play nice, why wasn't everyone signing up for it?)
There's three now. Time, Ruin and Memory. All are very good. Memory maybe a little weaker it might be one of those books that benefits from a second read.