Here is one main reason which Max alluded to earlier in this thread: there are fraud groups that originate from various locations: Finland, Israel, Denmark, Malaysia, and Poland just to name a few. Some of the casinos that have been hit hard by these groups (and I'm talking fraud, not just bonus baggers/beaters) will look at a common denominator (let's say bonus) and bonus ban the entire country. That is much easier and less time consuming (read: not as costly) than auditing each and every account.
All this stuff about it being analogous to racism or ethnocentrism is a bunch of hooey. I figure most of you can see beyond that.
So you live in a country where bonus play has a 99x play through requirement, well then just move on. Or better yet - free yourself from astronomical wagering requirements and play without one. You may find it refreshing