Turkey is an Islamic country. 99% of people there are Muslims. They would not fit in with Europeans. Also, since Turkey is such a large country, they would get a lot of power. That would be unfair for the other countries in the European Union. Also Turkey won't admit to the genocide of Armenians in 1915. They also tried to take Cyprus from Greece, which much of the EU did not agree on.
Turkey is a country with no respect to human rights. Turkey is a Muslim country with quite different culture then the European one. Turkey doesn't belong to Western Civilized world. Turkey belongs to the Muslim world. How it can join the EU? How can a country that kills and the Kurds and has illegal possession of the North part of Cyprus to join EU? How can a country that doesn't recognize the Kurds genocide join the EU? How can a country that sends to prison each person that dares to write an article against the government join EU? How can a country that doesn't respect its neighbors and threatens them with war join the EU?
Recent years show us that EU is a protective and unfortunately cannot make long term strategic decisions anymore. While Britain wants to leave the EU, its better for Turkey to be partner with US, Russia, India and even China.
Turkey can be a partner with EU in some cases but should not adopt its ways.
The main reason for Turkey to have EU membership is economical. Turkey's economy has never been stronger. They no longer need to have admission to the EU to improve their economic bottom line. It would serve them better to continue with favored trade status with the EU and maintain their independence from the EU. The EU has its own economic issues to deal with. Bailing Greece out over and over is not improving the economy of the EU. At this point, Turkey no longer needs the EU, but the EU really needs Turkey. Especially in light of the Syrian refugee crisis.
I think that Turkey would be more than a little bit silly to turn down the benefits of being a member of the European Union. While they are a bit different from other EU nations, they could offer a lot to the union, and in turn could get a lot for themselves.
Turkey should not reject EU membership because they could use the protection and the friendship from allies that are close to them and secure. If they reject it they are looking at a few friends close by and then more farther away. It is in their best interest to accept the EU membership.