Aren't both of those "blackmail"? (sanctions are simply a very specific type of blackmail, which is a more general term)
I guess they pick their vocabulary from the "Emotional Words" dictionary.
One of the prominent contracts not being followed is all those US banks freezing Russian USD holdings/reserves measuring in hundreds of billions of USD IIRC.
So I don't see that difference you are talking about. I mean, that's the purpose of sanctions, to stop doing business with a country (iow, stop honouring existing contracts in addition to not signing new ones) to make them change course. IOW, to blackmail them to change course.
It seems like you are disputing that sanctions are a type of blackmail? Perhaps both are better described as "extortion" instead, but "blackmail" applies equally well.
Again, this is an attempt to use more emotionally charged language for effectively the same actions. I am not sure why it needs extra explanation though.