Please explain "annexed"; your wikipedia link makes it clear that different people intepret scare-quotes in different ways. If you are talking about annexation not involving coercion, then we aren't reading from the same dictionary page.
In the sense that the current government in Russia still perceives its former satellites as part of it or its sphere of influence. The US and Russia are the main players here so I'm not considering the opinions of the people living in those states sorry but that's just realpolitik and its the way both sides think. Russia lost its empire during the collapse of the Soviet Union and the United States has been expanding its empire at their expense. Before you say anything about it not being an empire, I'll just say if it walks like a duck and quacks like a duck it's a duck.
1. NATO isn't a country, and can't annexe anything.
2. Former Soviet states are states that are no longer Soviet. NATO didn't ccoerce Poland and Lithuania into joining.
Your notion of what annexation means is at odds with mine.