We owe a debt to the diaspora, but right to vote would be step too far
No tax without representation. This was the slogan that powered the creation of the United States. It is not hard to understand why.
When Britain ruled its North American colonies from London, it did not give those living there the right to send elected representatives to Westminster. The inherent injustice of being made to pay tax, but having no say in what is done with the money, led to revolution. Ultimately, it led independence.
If the principal that paying tax earns citizens the right to be represented is now accepted almost everywhere as a tenant of democracy, it is curious that matters often don't work the other way round.