Without going into a deep philosophical essay, there are a number of reasons Nazism is a popular sign of rebellion in the Ukrainian right wing.
Firstly, during world war 2, Ukrainian (as well as a number of other Eastern European) independence fighters were supported by Nazi's; from their perspective the Soviet Union was a bigger threat to their identity.
Secondly, Nazism focuses a lot on folk identity. Ukraine had historic repression of it's identity as a country and strong nationalism helps bring it out. Nazism is essentially all about a folklore German identity being repressed by modernist forces, and indeed Ukrainian identity has been repressed by not only Russia but also it's modernist Soviet Union form.
Coincidentally, Germany's Nazism focused a lot on the agricultural, rural past of the country. Ukraine's identity is also heavily agricultural; after all it is a country that lies exactly on an extremely fertile streak of land (Chernozem) and a lot of Ukrainian folklore comes from an image describing rich fields, satisfied families living with full bellies, mystical bards travelling from field to field and so on- Nazism focuses on the unbreakable union of the spirit of man and nature, which for Ukraine is an integral part of it's identity.
Tl;dr - Ukrainian neo-nazis are not nazis in the sense you expect. Nazi philosophy compliments Ukrainian ideals on it's identity and that's why Ukrainian nationalists take up neo nazi insignia. In reality, they work with Jews readily (consider how many of them are in the ruling gov't) and have no central racist policy- parties like Svoboda / Right Sector focus on Ukraine's independence from Russian INFLUENCE, but those that have actual ethnic hatred are few in numbers.
They are not real Nazis.