Turchynov? You can say a lot of things about him especially that he's conservative, but not that he wouldn't be a democrat. But who was interim wasn't important in the first place as then there were elections.
Those were won by Poroshenko who was rather heavy-handed in the east, also socially conservative, which made people (for one or both of those reasons) vote for Zelensky -- an ethnic Russian, running on a "let's try to be friends" platform, but not one of those "let's just bend over for Russia and let the Kremlin rule the country" people, either.
Those are all descisions of the Ukrainian electorate. To imply that that was all the US reeks of conspiratorial American exceptionalism. Believe it or not things happen without the CIA having their dirty fingers in it.