Odysseus explicitly takes responsibility for Scylla devouring the six oarsmen:
. . . For my part,
I let go from my mind the difficult instruction that Circe
Had given me, for she told me not to be armed for combat;
But I put on my glorious armor and, taking up two long
Spears in my hands, I stood bestriding the vessel’s foredeck
At the prow. . . .
[Book XII, ll. 225-29; Lattimore translation]
Guilt drips from his reaction to the carnage:
That was the most pitiful scene these eyes have looked on
In my sufferings as I explored the routes over water.
[Book XII, ll. 258-59]
Who's to argue with the hero himself?
I think it depends on how you look at the situation. Odysseus was put in a tough spot -- to either sail by Charybdis and risk all the men being killed or sail by Scylla and know that 6 men would have to be sacrificed. I think he made the best decision; I also, however, think he can be blamed for not warning the men about what they may encounter on the water, though that may have caused hysteria.