Greece has many problems (corruption being one of the greatest). But it was perfectly up to standards to become an EU-member (not to become a member of the eurozone, which is part of the problem now).
When was the last year Belgium complied with €'s Maastricht Criteria (Less than 3% budget-deficit and less than 60% debt-to-GDP ratio) ?
Since introduction of € Belgium violated Maastricht each year.
You never even complied to the criteria. If Greece shouldn't have become €-zone member so shouldn't have Belgium.