First, that's a laughably false claim, and second, putin has been bombing Syrian since '15; "According to Amnesty International, in late February 2016 Russian warplanes deliberately targeted civilians and rescue workers during their bombing campaign.[497] The human rights group has documented attacks on schools, hospitals and civilian homes. Amnesty International also said that "Russia is guilty of some the most egregious war crimes" it had seen "in decades". The director of Amnesty's crisis response program, Tirana Hassan, said that after bombing civilian targets, the Russian warplanes "loop around" for a second attack to target the humanitarian workers and civilians who are trying to help those have been injured in the first sortie.[179][497]" I guess it's worth it to putin to maintain access to Syria's Mediterranean ports and of course to prop up a fellow blood soaked dictator.