I’m sure no one hates dolph for who he is - a sweet little boy who is interested in art and has no knowledge of his resemblance to hitler.
they hate dolph for what the writers intended him to be. the fact his character is littered with nazi symbolism is attributed to growing up in a german military camp - why not just say all german soldiers are nazis while you’re at it? not to mention, his focus episode was literally about him hunting down the only jewish kid at camp.
let’s face it - dolph is nothing more than a young hitler joke. what characteristic does he have that is not shared by hitler? ignorance of Nazism aside, nothing. dolph is also one of the characters with no distinctive quality - flip flopping between being nice and adorable (a quality he also attributes to himself) and roasting david on top of a fire for no reason.
(so he doesn’t step out of line until he does? what makes him act out? curiosity or fun seeking or disobedience? there’s nothing to quantify his character with and it frustrates me to no end)
there’s a fine line between satire/lampshading and just being plain awful. one of the reasons dolphs character is awful is just - its too soon. we are not even one generation removed from the Holocaust. I am aware there are other insensitive as hell media about this exact topic, but just understand why people can feel uncomfortable to the point they hate dolph.
tl;dr: people can hate whatever and whomever the hell they want.