What descent ? The sentinels and the hellfire club were running a muck . Wolverine went too far because the kids have a right to fight for their homes and safety if they want ! They aren't babies and as mutants especially . If he thought Scott was so wrong then he gave him the opportunity to take it too a vote where if he won he could help shape all the remaining mutants ( at the time;) destiny . He chickened out by half assing it since him and Scott both have valid view points that are better working together for mutant kind
The descent into a moral grey area that Cyclops has been entering since Eve of Destruction.
I'm not saying Cyclops's decisions from EoD and beyond were bad and not well-thought out, but they were clearly getting more and more morally ambiguous. Cyclops is the self appointed leader of the X-Men and more or less the mutant race, the methods he chooses to take will be followed (and likely to an extreme level) by all those that follow him. Over the years, Wolverine has seen these decision become less and less like the Cyclops he knew. It has NEVER sat right with Logan.
As far as Schism specifically, Cyclops was faced with a lot of hard decisions and many of which effected the lives of the kids and I understand each choice he made, but Logan took the stance that he shouldn't even be placing kids in those situations in the first place. Logan has always been willing to be "the fall guy" for Cyclops, from X-Force and beyond but he is NOT ok with Cyclops doing that with people not built for that life.