i have the same complaints that i did when i read the LN, they have absolutely no evidence pointing towards MC's dad being the culprit they also only have info from a person that they know is unreliable and hates MC to base his character and motives from. there is nothing at all showing that he's an enemy of mankind in fact the opposite, he cooperated with the humans after he came out of the dungeon and even saved civilians lives. it's such a bullshit plot point.