The real reason why Turkey may never join the EU is just old fashioned international politics. The EU Parliament’s seats are handed out by population size, and the more important commissioners’ appointments are generally handed out to the larger countries. Turkey would be the second most populous country in the EU, and would inevitably have a large say.
This explains France’s hostility. In the early years of the EU it was pretty much a French club. France could generally get Germany on-side because of post-war guilt, and the Italian government changed so often that their influence, along with all the tiny countries, was minimal. This was one reason why De Gaulle vetoed UK joining – it would have weakened France’s influence. As a newer and larger Germany has shaken off its post-war guilt and gets out from under France’s shadow, and UK follows its own national agenda, the influence of France on the EU has shrunk. If Turkey joined, with its large population, the influence of France would shrink even more.
Letting all the smaller Eastern European countries into the EU was a political matter which didn’t matter too much. They were unlikely to combine and weaken the influence of the EU’s major players, and it prevented them going unstable at the EU’s boundaries. Anyone who suggest that the Baltic States, Bulgaria or Romania are models of liberal democracies in fact (as opposed to on paper) should try doing business or living there. Turkey is essentially stable so doesn’t need to be brought into the club in the same way.
Don’t let passion get in the way of real politics, real politicians rarely do.