I believe the parent was making a rhetorical point: if your base fatality rate were 50%, then doubling it would mean you’d be guaranteed to die. Therefore, saying something “only” doubles your risk of death can understate the impact of what that doubling means in practice.

It's pretty simple: at my age randomly dying isn't something I'm concerned about at all. So doubling those chances is still not something I'm concerned about.

It's certainly not an existential threat to society.