Who would? But how do their ideas contradict evolutionary thought? Isn't natural selection constantly improving us, as we are constantly evolving?
They're just speeding up the process.
It stops being natural selection then. Of course we've been screwing up natural selection for a long time. The first time a doctor kept a kid from dieing from some disease and that kid went on to have kids we broke natural selection.
Life extension & transhumanism (which seems to be <ahem> life-extension on steroids) are both orthogonal to evolution. Why would you think there was any relation between the two? Are you saying that a creationist shouldn't want to extend their lives or try to ensure that they'll still mentally alert when they reach 100? How strange.