Natural selection is driven by pressures that affect reproduction chances

Oh, like dying of old age at 28 of a broken foot or a fucked up tooth?

Like a genetic mutation that makes you sicker

In nature it's what cleans the genetics of a species of disease over time, preventing infinite accumulation of negative mutations

If you think that's all that natural selection is, you're woefully uneducated on the topic. Because natural selection does in fact include external pressures like predators, disease, and accidents, along with genetics. Genetics can absolutely make a difference in making it to reproduction, but environmental factors are just as big of a factor, if not bigger, in making it that long.