If you're happy to die, why be bothered by others' trying to live longer? You won't be around. And assuming people can finance it themselves, is it really a problem for society?
I'd also say people may want more life for themselves, but what does that mean at scale, forever?
There are many reasons that people living forever would be a problem for society, the most obvious being an ever-increasing population.
Child mortality is very low now compared to the past, thanks to the modern medicine and technology.
I am glad humanity "played God", and reduced this unnecessary child suffering.