It's important to realize the 21st century was nearly brought to its knees by something not even alive. It's a pure instruction set. It can only replicate by manipulating the host to photocopy it; reprograms what it invades.
It seems alien because the 20th century mind saw information as the epiphenomena or 'dream' of the material mind. Yet that 'dream' possessed a reality they little guessed.
HG Wells saw the alien as bug eyed monsters from Mars arriving in steel cyclinders shot across physical space by gunpowder. But maybe the really dangerous aliens are thoughts we have not yet thought or information nature has not yet crafted waiting quietly just round the bend.
