Are you living in the UK or just making baseless assumptions? For an ever-inceasing number of serious health issues, the NHS has been essentially non-functional for many years. I have friends with chronic conditions that are looking to emigrate becase they're dreading their health getting worse in a system that's doing nothing to help them.
"NHS would be great except for the bad politicians" is not a serious argument.
It's underfunded. I'm willing to bet that the countries they're thinking of moving to either spend more on healthcare as a proportion of GDP than the UK does or don't have healthcare that's free at the point of use (or both).