The same reason why you have barrels, throwables and ranged enemies spamming them everywhere.
As soon as JD says something nice about this game, Larian will have created something so perfect it will be considered a divine artifact and the second coming of Christ will be nigh.
On topic though: Wyll and Gale both mention they've been considerably weakened by the whole ordeal. I guess the rationale is the whole gang kinda got an unstandard treatment with the spaceship crash and all.
From the Duke abduction we can probably deduce they don't go around abducting farmers but people of certain talents and/or influence.
Now on a personal note I agree I'd much rather be running around with this lot than a bunch of random farmers/shepherds/miners.
