Here's some more points, that the short Wiki article doesn't fully address

The class-conscious proletariat can give its consent to a revolutionary war, which would really justify revolutionary defencism, only on condition: (a) that the power pass to the proletariat and the poorest sections of the peasants aligned with the proletariat; (b) that all annexations be renounced in deed and not in word; that a complete break be effected in actual fact with all capitalist interests.

In view of the undoubted honesty of those broad sections of the mass believers in revolutionary defencism who accept the war only as a necessity, and not as a means of conquest, in view of the fact that they are being deceived by the bourgeoisie, it is necessary with particular thoroughness, persistence and patience to explain their error to them, to explain the inseparable connection existing between capital and the imperialist war, and to prove that without overthrowing capital it is impossible to end the war by a truly democratic peace, a peace not imposed by violence.

Though Revolutionary Defeatism necessitates the "revolutionary class" desiring and facilitating facilitating "the defeat of its government". Revolutionary defeatism isn't a moral or ethical stance that means "both sides are bad, therefore we should desire the defeat of both", it's a practical strategy for revolutionaries to pursue:

revolutionary tactics that are quite unfeasible unless they “contribute to the defeat” of their own government, but which alone lead to a European revolution, to the permanent peace of socialism, to the liberation of humanity from the horrors, misery, savagery and brutality now prevailing.

Revolutionaries in Russia should desire their country's defeat in Ukraine, while those in the "West" should work towards the defeat of NATO. No one should condemn domestic opposition to the war effort in any country without a revolutionary government.