The member may very well be right. I am not stating my position with any confidence, but I would say this. There is a difference between mutually agreed adjustments to borders on the one hand and the seizure of territory on the other.
In the case of Russia and Crimea, there was no negotiation. There was no agreement. It was brute force, and similarly in the Donbass.
I would distinguish between what nations have done throughout history, and that is to say, look for ways of accommodating one another's interests at a price they think is worth paying, on the one hand, and what the Russians are doing on the other, which is a flat contravention of the basic principles of the post-World War II international order.
However—