According to Anna Soroka, representative of the Luhansk separatists, it is necessary for the EU to realise that the prevalent rhetoric in Ukraine is that of radical nationalism.
Visa-liberalisation for Ukrainians will lead to fewer working opportunities for Czechs; it may also lead to the spreading of Ukrainian mafias and ultranationalists into Europe. Ukraine is violating the rights of whole groups of its population.
The visa liberalisation will grant Ukrainians only short-term visits to Europe (90 days every half a year), and is not connected to the issue of labour liberalisation for Ukrainians. The visa liberalisation doesn't mean abolition of border security checks. Furthermore, all Ukrainians seeking to use the visa-free regime will have to posses a biometric passport. (More details on the visa process here).
Ukraine has no policy of repressions towards any of its population groups.