[vanusa]

Did he realize that NATO did not invade these countries, like Russia did to Georgia and Ukraine, and NATO membership is the choice of its people?

Say what you will about events that have happened since then. But the basic fact is, the Russians were explicitly promised there would be no NATO expansion in the former Warsaw Pact countries (let alone in the former Soviet republics) all throughout the German Unification talks. Though it is virtually absent from the current public discussion, information on this is very easy to find, should you feel inspired to do so.