Here in Belgium there's been some friction in recent Olympics about the fact that the Belgian Olympic Committee often has more stringent participation criteria than the Olympic Games themselves - refuses to bring some athletes even though they are eligible to participate in the Games based on their results. So the question is whether participating in the Olympics is an athlete's right, when he or she fulfills the IOC's requirements, or whether the national Olympic Committees should have the right to decide who goes and who doesn't.

If you hold the latter view, then it seems only logical enough that the Greek Olympic Committee would decide not to bring her - they can do without the bad publicity, and it's not as if Greece has a good reputation to begin with at the moment, either in sports terms or in general terms.

Incidentally, the translation I saw of the tweet on my local newspaper's website was more offensive than yours, mentioning "homemade food" rather than just "food". You may have to go dig up the Greek original.