- An economic sanction does not kill people (not directly nor quickly).
- Economic sanctions mean simply that other countries do not want to trade with you. That is not fighting, is simply a effect of failing to have a successful relation with the international community.
- Economic sanctions are reversible. It is Putin's hand to take the steps to come back into the international community.
Yes, to us reasonable people, if you put it as much as objectively possible, that is definitely not a declaration of war. However, when you try to justify your own decisions you tend to go to the lowest possible threshold to legitimize your actions. In Putin's eyes (maybe fake but at least the rhetoric is like that) this is not aggression but a special military operation where they are not at fault and therefore there's no need for the west sanctions. It's complete crap, but that's the idea behind it.