> Would you define Russia not nuking Ukraine as "strict pacifism"?

Nobody reasonable would. Russia started a war of choice. That's the opposite of pacifism.

Strict pacifism would be Ukraine refusing to fight after being invaded. Someone saying all war in all circumtances is evil and should not be contributed to, directly or indirectly, is sort of endorsing that view. The folks calling for nuclear disarmament, or no first use policy, are pretty far away from that.