For instance, the event with Evo Morales' plane being forced down in Switzerland, while not exactly the same, clearly set a bad precedent and we're paying the price now. I don't have any problem with saying that what Belarus just did and what happened then with Evo Morales' plane were both wrong. (At the same time I support European countries sanctioning Belarus even if they were the same countries that just a few years ago denied their airspace to Morale's plane for political reasons.)
https://en.wikipedia.org/wiki/Evo_Morales_grounding_incident
On the other hand, if Ukraine did this just to harass a journalist saying things they didn't like (once again if we take the RT article at face value), then that's a questionable action that deserves to be criticized.
Lots of people using 'what about' are doing so to try to make reasonable comparisons between two cases. Lots of people do it to avoid blame or confuse the argument. You have to actually read to figure out which it is.
After some thinking it seems a lack of authority on what 'Truly' constitutes a logical fallacy during a conversation, but claiming the other is using a fallacy is a fallacy in it's own right. May I suggest Fallaception?