What does an occupation army do when it is installed in a country? It occupies the land, forcing residents to follow its own way of life. It implements measures against the country's inhabitants, it propagandizes its beliefs and uses force to have them imposed.
This, sadly, is what has been happening in Greece from the migrants who seem to "forget" that they are hosted in Greece and force the Greeks to feel like guests in their own country.
If someone is a war refugee or his life is in danger in his homeland, it would seem appropriate, when he arrives in the country which offers him asylum, to be grateful to this country, respect its history, its people, its values and its laws. The same would hold true for an immigrant who wants to go to a country where he hopes he will find a better future.