I too support Mandarin as the unifying language for China and for all Chinese elsewhere.

Like you, I also do not agree that language should be a "litmus-test" for being Chinese either by identity or nationality. That would be a prescription for division.

In general, I favour whatever unites and disfavours anything that divides.

There will always be the issue of snobbery (or language imperialism). After all, there are countless regional accents to spoken Mandarin. That's just the human weakness of narcissism - of loving all that is like one-self and creating artificial divisions from others - a sign of character weakness rather than strength.

One hopes with greater openness to the world, even 1.3 billion people will find more alike with one another than with the remaining 4.6billion. And once we realise that we are one planet among billions, we will realise we are all in this together.