I would have agreed with you had Russia accepted that it made a mistake. In the absence of something small as an acknowledgment and a formal apology (followed up by large monetary compensations for the victims’ families), it isn’t obvious to me how anytime can assume it was an accident.

The apology should have come immediately after the incident, without anyone asking for it.

It's not what happens to you, but how you react to it that matters. - Epictetus