Answer:
Yes, his decision not to inform his men of Scylla's danger justified because he knows that his men, already scared and tired as they are, will be more scared to even move forward with the journey ahead.
Odysseus depended on his own might and forgot the warning of Circe about Scylla's power which resulted in the death of six of his men.
Explanation:
If the men had known the dangers of the coming journey, it is highly doubtful none of them will ever want to be a part of it- "in case my comrades, overcome with fear,/ might stop rowing and huddle together/ inside the boat" (290-292).
Circe had already warned him about the danger that will be upon them when they go through the two rocks of Scylla and the murderous Charybdis. "She's not human,/ but a destroyer who will never die--/ fearful, difficult and fierce-- not someone/ you can fight. There's no defense against her./ the bravest thing to do is run away./ If you linger by the cliff to arm yourself,/ I fear she'll jump out once more, attack you/ with all her head and snatch away six men,/ just as before" (148- 156)
So, whether Odysseus arms himself or not won't be of any help. Instead, it is best that they work on moving past the rocks as soon and fast as possible and get out of that place. Only then will they be safe of Scylla with her many heads. Circe's bidding about arming himself had slipped his mind and he began charging for the fore-deck of the ship, only for Scylla to bring disaster on his companions, just as Circe had predicted. This reveals that Odysseus may have been too preoccupied in his attempts to steer clear of the disaster that he heeded not the advice of Circe and depended on his own might.
