I understand your sentiment. I think it would be more appropriate to say that “the world” should react, not “the West”.

And its world’s business if some country unilaterally declares other’s country part as theirs.

Although I think the world reacted appropriately. Non-trivial sanctions were imposed, almost no other country recognised the change.

Of course, Crimea issue is just another example of conflict of “territorial integrity“ vs “right to self determination” principles. World needs more formal rules.

(В любом случае, как мне кажется, справедливый референдум включал бы вариант «независимая Крымская Автономная Республика».)