Being the guy with the most nukes lets you get away with similar things. Nobody was brought to justice here, either. Two commanders did receive medals for their tour there, though.
this is not even the first time the russian/soviet military has been involved in shooting down a civilian airliner. The last time it was even more blatant and no one did anything https://en.wikipedia.org/wiki/Korean_Air_Lines_Flight_007
How is this relevant? Because country A murders people, country B may freely do so too?
I don't think he / she said anything about it being okay I think he / she was simply saying it's happened before with another powerful country.