The ignorance of this thread. You are making it sound like you are going to a another planet and want to know if the local aliens are hostile or not.

Greece is a developed western country, and has a large amount of tourists, millions of them every year, and a very developed tourist industry (one of the most developed per capita in the world) and has been doing it for decades, and is happy to take your money, and doesn't care where some of the snowflakes are coming from.

I personally didn't like Athens that much, but the islands are great to visit. The whole region (from Greece, Albania, Montenegro, Croatia, Slovenia, and all the way to Italy) is a blast to visit.