Double taxes to support Africa?

How would you answer the following question: "Many people leave Africa to live in Europe or North America each year. What do those people owe to their nations once they leave?"

Some countries, like Eritrea require that duel citizens pay income tax. Yes, this means that an Eritrean who moves to London would be required to pay taxes on their income twice, once to the English government and again to the Eritrean government. Recently, the government representatives in Germany decided to require an additional 300, 150 or 50 Euros from all Eritrean-German citizens depending on if they are employed, unemployed or students.

What do you think? Should African people be required to pay to keep their citizenship even if it means paying income tax to two different governments? I ask primarily because almost all Africans who leave "home" send money home regularly to support those family members that they left behind.

Tell us what you think.

Blessings,
Mama