NIC's build up entitlement over time for example pension rights which are payable oversea's to non resident British Citizens.
NI was a system designed to entitle people to access to the NHS and to Unemployment benefits, Pension rights came later.
Many people living abroad will continue to pay voluntary NI contributions in the UK in order to retain full pension rights, so what exactly is different about the NHS?
It may be the rules but it's not morally right when someone has paid their dues over many many years for them to be refused treatment because they choose to live abroad for a few years.
If your home base has absolutely irrevocably changed then yes I can see your point but few people moving to the Philippines are going to cut themselves off from the UK that way, they may well still have taxable assets in the UK and may well still be paying tax in the UK on payments from their pension annuities and other investments etc.
So should they be refused treatment just becuase they have been out of the country for x length of time?
Jim