I would understand using Ukraine's example to argue the exact opposite, but for some reason you believe that a first sign of aggression justifies dismantling all defenses.
There is precedent of NATO interfering in armed conflicts outside of the borders of their member states. They did so in Bosnia and Herzegovina and Kosovo during the Yugoslav wars. They also did so in Afghanistan and Libya (come to think of it; NATO has demonstrated it self to be more like an invasion pact then a defensive one). Why didn’t they act in Ukraine? You tell me.
Now again, there are non-intervention ways of punishing Russia for this blatant violation of international treaties, such as boycotts or sanctions. However all of the 10 NATO members that qualified opted to participate in the 2018 FIFA world cup hosted by hostile Russia. How is that for solidarity?