
Kagi isn't the problem with the touch, and the fact Hirano decided to try and find another way to show his affection is proof that even if his "romantic" feeling isn't the same, he cares a LOT. There are always fellow aro/ace people talking in here about how obviously he's One Of Us and it looks true. Just because "romantic attraction" as you know it isn't there doesn't mean romance and love aren't there. You or anyone else aren't lesser for not experiencing it the same way.
Anyway, Hirano is uncomfortable with another person initiating touch with intent beyond what he understands, and we know he isn't used to touch Like That. He has zero trouble with the affection when he initiates or when he has control of it. The hug isn't the problem. The form it takes is. Him "connecting" that his experience of feelings is different even though he also wants to do things and be close to Kagi is a positive thing. It's not a rejection, nor is it stringing Kagi along. It's just a different way of experiencing love.
Super cute. This mangaka does such wonderful soft shonen ai