Its about ensuring that Germany can't turn around and cut a deal with Russia. So far Germany has been the weakest link against Russia, barely contributing money to Ukraine and dragging their feet on giving weapons.
A few days ago Russia said this;
""The bottom line is, if you have an urge, if it's so hard for you, just lift the sanctions on Nord Stream 2, which is 55 billion cubic meters of gas per year, just push the button and everything will get going," Putin said."
STORY: Speaking to reporters after the Shanghai Cooperation Organisation summit in Uzbekistan, Putin blamed what he called "the green agenda" for the energy crisis and insisted that Russia would fulfi...
news.yahoo.com
And there has been an increasing number of protest in Germany over gas prices/imports. But now Germany doesn't have a choice, any possibility of receiving gas through Nordstream 1 or 2 is gone.