Board Thread:Naruto Discussions/@comment-31338621-20200326215538/@comment-34656247-20200327040504

It's the reasoning of the elders, mainly Danzo.The clan was heading for what seems like war. Itachi acted and fell prey to logic used by Danzo, the latter said:
 * Hiruzen would choose the village in a heartbeat to protect from war (true)
 * Kids must also be killed because they will grow up with a vengeful heart against Konoha.
 * Die along with the clan with an onslaught from Danzo, Hiruzen and Black Ops members which would include other innocents being killed or slaughter the clan and save Sasuke who knew nothing whilst saving the village from war..

SO yeah the logical choice was to slaughter the clan imo.