Every comment that I've read supporting Greece leaving the Euro has fallen into 1 or more categories:
1) Complete lack of economic understanding,
2) Unrelated argument or logic fallacy,
3) Ignoring that, no, it's not going to work out. Numbers don't lie.
The entire situation seems to come down to Greece spending others money then refusing to pay it back. That's theft.
As for the Euro not supporting Greece's tourism economics, can someone go into more depth? The point of group economics is that labor costs will even out - if someone is out of work then they will either work more efficiently or work for less compensation.