You guys keep posting simialr question daily instead of checking threads already posted.
Danzou was a rigid leader, Sarutobi was not and believed in finding a solution in an amicable way. But, Uchihas themselves had the same kind of thinking as Danzou and refused to talk and discuss the whole issue openly to resolve it.
Fugaku and others could have considred reasons and possiblity of Kyuubi attack and think who among them could do it just in case. Itachi did find Tobi somehow after all. Uchihas had asked Shisui to spy on Itachi when he showed disagreement with clan's way of thinking. That backfired for them off course, unluckily, when Shisui turned a nationalist as well.
They were suspected and instead of coming out and tell their side of the story(if they had) and discuss it before making any attempts of a coup. Hiruzen let Hizashi die to avoid a war even if the demand was unreasonable. He would have listenned and even Tobi accepted it.
Clan was having secret meetings to make the plans and survivors if any would have suffered more hate and suspecion even more after all the shinobies were sentenced and the whole cycle would contiue. Have you thought that the coup Uchihas were planning would have killed childrens too?
Uchiha clan was dealt in the manner feudal lords dealt with such act as rebellians and efforts to start a war. Are you telling us that the whole of Uchiha clan wouldn't have followed the leader Fugaku and wouldn't have contributed to the civil war just because they may not be established shinobies? That's pretty niave thought and only tells that you do not know what happens during such wars.
It was a sad situation but Uchihas themselves are to be blamed as much as Danzou. They brought it on themselves knowing the implicatins but ignoring it.