You are comparing apples with oranges here. For Allah is not like you. You are a limited and finite human being. Justice demands that the punishment must fit the crime. The punishment committed against your mother is that of finite magnitude, thus calling for a finite punishment.

However, Allah is infinite and beyond limitations. Thus, one who rejects the infinite God for no valid reason (e.g. he wasn't insane, he wasn't in a coma, he received the correct message, etc.), has committed a crime that is of infinite magnitude. Thus, since the punishment must fit the crime and the crime is that of infinite magnitude, objective logic demands that the punishment must also be infinite and that is burning in hell forever.

Objective logic states that a crime commited against the infinite God should draw in an infinite punishment. But it is our emotions and personal subjective opinions that say other wise.

Also, we tend to look at the magnitude of the crime (e.g. simply rejecting a religion) but we do not tend to try and imagine the magnitude of whom the crime is being committed against.

Also, simply not liking, understanding or agreeing with something is not evidence against that thing. For example, in China you have people who commit tax evasion being executed. Now, I don't agree, understand or like that law, but that does not change the fact that the law is a reality in China.

Similarly, not liking, understanding or agreeing with people being burnt in hell forever, is not evidence against its reality. Us Muslims submit to the truth rather we like it or not. We don't care about what people like, agree or understand, we care about the truth. If the truth is something that we don't like, well then as the saying goes 'Truth hurts'.

Allah knows best.