this is a dumb argument. It's like saying "the man flew on a plane from China to the USA but then tripped on the stairs on the way into his apartment? not very likely" - just because he used a technology to get there, doesn't mean he created it, knows how it works, any of that.. maybe it autopilots through space but the user has to take control in the air? maybe they just commonly crash in the last "mile" of their journey like humans, regardless, it's a bad argument. I don't think aliens or alien spacecraft have visited earth, but the "how could they travel space but then crash here" argument doesnt hold much merit for me