He's only following his leader.  Kirill has had a painful thunderstick for Ukraine since Bartholomew I granted the Ukrainian Orthodox Church autocephaly from the Russian, which caused Kirill to immediately sever all communion with Ecumenical Orthodoxy (Which leads me to wonder whether the Russian Church can still be called Orthodox, but that's not my fight.).  Not a huge surprise given Kirill was a KGB agent, as was his predecessor Alexy II.