AIBU to ask What Rights

[GinUser]

UK citizens living in Europe actually have?
If you have been away from the UK for more than 15 years, you lose all rights in the UK. In most other countries you have no other rights, except permanent residence or the right to buy property. Certainly no voting rights.

The right to work

Education? Healthcare? Shelter? Freedom of speech? Religious freedom? Not to be tortured?

You don't "lose all rights" in the UK. You cannot vote if you are still away from the UK after 15 years, but why should you be able to? You've been absent for a very long time. If you return to a British address, you can vote again provided you are a British citizen.

why should you be able to?
Because British citizens abroad are still affected by British legislation - not least, Brexit.