Although it's true that there are copious amounts of anti-German rhetoric in local media, it's mostly targeted towards German politics and politicians, not Germany in general or its people. Ewald Lienen, a German football coach who has been working in Greece for a few years, was recently asked more or less the same question by the Bild and his reply was:
I feel no animosity or German-hatred. On the contrary, they are all very courteous and friendly to me. I was not ever insulted, because I'm from Germany.
As a tourist, even if you were misidentified as a German, you wouldn't really be at risk, at least not more at risk than if you were Greek. And the Netherlands doesn't really come up in fiery crisis related talks (and why would it?).
To generalize the answer a bit, tourists from the EU don't really have anything to fear. Yes, it's possible that you might get a snarky look (or two) if you're German, but that's about it. Greece has a very long tradition in tourism, it's part of our culture and essential to our frail economy. As choster already mentioned there have been no reported incidents of violence against tourists since the crisis began.
If you do decide to visit Greece soon, and you happen to get into a political discussion with a Greek, just agree with whatever they tell you and you'll probably get a couple of free beers out of it ;)