i'm actually not even bothered by scorer giving the batter a hit there. a hit only pisses off 1 person, an error pisses off 2.
but X needs to at least knock that ball down, if not catch it with leather. what he did allowed the runner to get into scoring position. IMO that's what makes it "boneheaded". situational awareness. go-ahead runner on 1b in the 8th inning is 73% less stressful than a runner on 2b in that situation.