isaac was never good at deciphering who was his friend and who actually hated him when he was little. he would pick someone to be friends with him and follow them around like a puppy, if they told him to leave them alone he would simply giggle and think they were joking.
kids on the playground would make fun of him for all sorts of reasons. whether it be his little moles he had on his back and tummy that would be visible when changing for pe, or his speech impediment that he never seemed to grow out of. there was always something. when his heart stopped working properly there was just something else for them to mock him for. he was weak in their eyes.
when he got to nevermore he thought things would be different. he thought a school full of weirdos and outcasts couldn’t bully you for being a weirdo and an outcast. he was wrong.
he did his same routine. he found you and decided to latch onto you. he followed you around and expected you to listen when he spoke about his inventions.
you don’t dislike isaac, you just think he’s a bit weird.