It's amazing how often this warped logic is used, and a lot of times stupid cliche happen "noooo, it's all my fault, wwaaaawaaaawaaaa"
Let's say you come back home and there's a person there, who murdered your whole family, and they tell you, they did it, because of you, because they want to have you (or some such). Don't be stupid, the murderer is at fault. I think the trope is more commonly used in the tragic past setting, where the MC blames themselves for all the irrelevant stuff that happened to their close ones.
But yeah, that tenko boy's just messed up.