We don't mean he's going to abduct everyone. He's going to surround the town with trees, use their interconnected roots as a net, then use his telepathic woodpower to propel the town into the depths of space, where we assume everyone would asphyxiate immediately.
"Trees are really bad at science."
But every alien invasion has its dumb Achilles' heel, and Groot's insane scheme was foiled by termites.
"I also invented something I call 'fire' as a backup!"