You're forgetting that national souvereignity dictates the people within a nation (or actually its government, but let's assume that in proper democracies that's the same thing) are the only ones who can decide which alliances or treaties a country wants to be a part of, or not. You cannot defend a Brexit and than proceed to say Ukraine has no right to request membership of the EU because of apparent secret dealings. Either you're a full-blown Offensive Realist and you should argue the EU should invade Britain to avoid a secession, or you're defend national sovereignty, but you really can't have both.
Ukraine has been working at improving her institutions, economy and democracy ever since independence and the role the European Union has played in this, however minor, is something to be proud on. There is no grand regime-change-conspiracy, as much as you'd love there to be.
Internal division on the European Union is surprisingly small, by the way. 51-55% of Ukrainians support joining the EU, while only 15-19% support joining Russia's Custom Unions, with the rest either wanting to join both or none. 43% of Ukrainians would vote in favour of joining NATO if a referendum was called, against 29% against. Invasion tends to change perspectives.