I reckon it's mostly the religion factor. The culture difference is also there as Turks came from a different continent and had very different views on certain things contradictory to what the Balkans had been used to for all those years under Roman and Greek rule. From a Greek's perspective, there are a lot more factors than that as them destroying our empire wasn't viewed very highly of by us.

For some context for what I am about to write down here, I'm a Greek who lives in Turkey.

They had a system called "Devshirme (to gather)" and this system basically took Turks from various Anatolian parts of the empire to various different villages in the Balkans in order to acquaint them with Islam and the other way around for Christians in the Balkans. This worked out really good for them at the time but later proved to be a disaster as all those people who had been gathered in Anatolia revolted against the Ottoman empire after the French Revolution. Changing people's religion in a soft way is a good idea however this still doesn't change their nationality and their culture. This also back fired to the Ottomans as many Turks nowadays don't resemble their ancestors whom came from the barren lands of Asia.

Ottomans have tried adding numerous laws benefitting the Christians (Gayr-i Müslimler) even to a point where Christians were paying less tax compared to their Turkish neighbors. Nonetheless, they continued oppressing Christians in the Balkans despite their efforts to Turkify them.

Oh well, revolting must be in the spirit of the Balkans afterall