I'd add that thinking over alien invasion is, IMO, more straightforward than speculating about AI. Ironically, if I remember correctly, it was prof. Hawking that was against looking for aliens because "they will steal our resources"
Which resources? you mean things like....I don't know...water, sand, metals, hydrocarbons.....stuff in general. Stuff, that can be found in vastly, hugely, mindbogglingly enormous quantities EVERYWHERE else but on planet Earth for example. You mean those aliens who would have the technology to cross the interstellar distances won't have the option to mine asteroids or take resources from the unimaginably huge quantities of cosmic debris; from planets [the vast majority] that would never harbor life; are they gonna burn OIL in their FTL engines? And even if they do they'd come for our oil rather than look around for their local version of Titan!?
This is soooo nuts that I am afraid I lost my trust in the man altogether.