It is becoming more and more annoying. This dude lived more than ten years in modern world (from the look of it maybe even fifteen, but lets take minimal estimation), then about other ten (current age minus initial years without awareness), then trained for five years in another dimension, where...
You know, and there will surely be a lot of angry people disagreeing with me, but even given the fact that children are usually stupid, author portrayed them in such a way, that i am not even feeling any pity for little shits.