The commonwealth vote is already here. Tbh, really, I don't think anyone who lives out of the country for a prolonged period of time should have the vote either, apart from things that may directly impact on them, pensions etc.
How would that work? Constant referendums and then sorting out people by age, profession, country they now live in?
Just because the commonwealth vote was seen as logically 60 years ago, it doesn't mean it is still valid today. Out of interest, can UK citizen vote in Australia, South Africa, India etc?
Well clearly you're not commited to the UK if you got citizenship and then left. That doesn't sound right either.
When we filled out the naturalisation paperwork, one question actually is "In which country will you have your permanent home" (or similar). I joked with DH and wondered what would happen if I wrote Germany. We didn't but even having this question on the official paperwork made it a bit of a joke.
The issue is, you don't know what your future brings. To have citizenship the poster must have been here for years and most likely saw herself as settled and wanted to stay. But circumstances change. Maybe she got a job somewhere or fell in love. My current HR boss. has to relocate back to Brazil for an unknown amount of time due to family issues with her parents.