[superchroma]

Because countries don't always act on principle but almost always try and do things that will benefit them politically or strategically. There is nothing to be gained in a political or strategic spectrum by unravelling the space co-operation relationship. Putin + Rogozin already saber rattled on the topic to signal things to the Russian public, and Putin's key problem is his faltering war. The actions of astronauts are not meaningful.

The same is true from the US perspective, except this way they can demonstrate an ongoing commitment to stability, co-operation and science.

You may as well ask why not declare all Russians in the US as persona-non-grata and deport them?