Essentially I see the Ukrainians as a people searching for an identity and the best way is to say who you are not.
This is due to their history -- as the birthplace of Eastern Slavs (Muscovites, Belarussians and Ukrainians), they want to link to that past, but that's gone. The Mongols destroyed it and then the 3 East Slav regions went under the Influence of Mongols (Muscovites), Lithuanians (Belrusyni) and Poles (ukrainians). The Ukrainians under Khlemnitskiy made a pact with the devil signing up with the Muscovite Tsar. Since then for 300 years they have been the in-betweeners
Communism exacerbated this -- this is a land of people who self-describe their nationality as "tutajsi" -- "from here only". They have never been allowed to create a sense of nationhood greater than the local area. And let's not be proud of other nations that HAVE -- this sentiment is only 200 to 300 years old in most of the world.