It's military dog whistling. "just letting everyone else know that we can shoot down your satellites, so don't mess with us'. It's deterrent.
Unfortunately the US started it back in 2008 when they shot down one of their own spy satellites supposedly for 'safety'. Hmmmm
http://www.planetary.org/blogs/emily...2008/1327.html
Now everyone that joins the club has to do it too.
Markus