Evil vs Evil
The attack by Islamic State terrorist in Moscow was an act of evil. 133 innocent people died. Islamic State is an evil organisation.
The response of the Putin Government was also evil, albeit in a lesser way.
The United States privately and publicly warned them of a likely terrorist attack on a concert, based on intelligence they intercepted from Islamic State.
Islamic State has publicly claimed credit for the attack.
Yet the Putin Government is publicly blaming the attack on Ukraine.