On the surface it might sound that there is some sort of discrimination based on ethnic and/or nationality issues. I do not think that is the policy here. The reality is that it requires added incentives to persuade Westerners to relocate to Qatar. For some other nationalities, the prospect of getting a 10-15 times currency exchange benefit is a whole lot of incentive by itself. Among other reasons.
It is just a reflection of the realities. It should not be meant to be discriminatory. They just want you get here and work for them, not naturalize you.