THE RED LINE IN UKRAINE

Putin drew a red line in Ukraine against NATO expansion.

As you can see below, NATO has been slowly marching east since 1990. NATO countries took in the Nazi hierarchy at the end of WW2.

And Russia has many, many bad memories of the Nazis.

So:

1. why did NATO take in the Nazis?
2. why is NATO provoking Russia in Ukraine?
3. why did Zelensky renege on his promise to implement Minsk II and call for the ethnic cleansing of Russians from East Ukraine?