User blog comment:Dragonzzilla/Describe Your Mass Effect 3 Ending/@comment-1978336-20120903210327/@comment-24174486-20120904000344

"It is the only way to end the Synthetic vs Organic conflict."

It's the only way to end the possibility of synthetic/organic conflict.

"The Catalyst states that if the Destroy option is chosen 'he will be forced to create a new solution', implying that he will not be harmed and that he will not stop the cycle of extinction, and by extension that Shepard's actions in the Destroy ending are ultimately only a setback for the Catalyst."

When Shepard reaches the Catalyst, it has decided that the Reapers are a poor solution to the "problem" of organic/synthetic conflict, which is (at least part of) why the Catalyst helps Shepard to decide upon a new "solution", even if their choice does not address the Catalyst's "problem" (a.k.a. Destroy). While the Catalyst may try to find a new solution, I doubt it would decide on a new generation of Reapers.