I was about to post an enhancement about this and coming from Sync and Relay, I expect that tapping on a comment with child comments would hide just the child comments, while leaving the main comment fully expanded. And for comments without replies to have no change. But not all apps do it like this.
It seams Jerboa follows the official reddit app in hiding comments, where all comments are hidable, regardless of replies. And the tapped (parent) comment is the one being hidden.
I am not sure which behavior is better (I prefer the former, like you), maybe this should be a toggle? If the current system is the intended behavior, then a truncated bit of the comment should be in the hidden comment. i.e a comment saying "Lorem ipsum dolor sit amet, consectetur", when hidden would read: User "Lorem ipsum..." 5 • 1h