it's certainly much more difficult to forgive someone for killing your own child, i'm not saying it should be easy, but if it takes a great deal of love and humility to forgive in such a circumstance, then what is it when we choose not to forgive?
grief, being an emotion, as i said, does not constitute unforgiveness, forgiveness is in the will, and so is it not pride when a parent willingly refuses forgiveness?
the grief is one thing, and if it takes time before one can forgive, that is understandable, but how can we expect to be forgiven ourselves for killing the son of God by our sins, if we cannot forgive likewise someone for killing our own child?
a parent can grieve for their child, but also grieve for the poor soul of the man on the road to hell, and wish for his conversion,
it's not just the difficulty of forgiveness that's pride, it's the knowing and willing decision that "i will not forgive"
and it's one thing to forgive someone for killing many others which had nothing to do with you, forgiveness is personal, you forgive someone for what they have caused you, you choose not to hold the wrongdoing against them(which does not mean they should not go to jail, it just means you do not harbor hate or ill will towards them)...when someone kills your child, they have taken something from you, and therefore it is very personal,
you can personally forgive someone for what harm or grief they have caused you, but forgiveness of a person who has killed many, or rather, forgiveness of their sins, is Gods domain, and has nothing to do with you, so that is entirely besides the point, we forgive for personal wrongdoings, not the sins of others.
but i think to explain it better i will need to explain what pride is, and how bearing a grudge, under any circumstance, is rooted in pride.
first of all, we know pride is the root of all evil, meaning, all sin stems from pride, and pride itself is the vice of lies, it causes an inordinate esteem of oneself, making us think we are worthy of more or deserving of more than we get, or not deserving of what we do get, or it makes us think more highly of ourselves and glory in things as if they did not come from God...that is a basic explanation of pride, and it goes much more deep than that, since you can connect every sin with pride, but in regards to this particular sin, namely, the refusal to forgive, the pride lies in our thinking that the crime against us is to great to be forgiven, and the reason it is pride is because it's simply not true, if we are of the opinion that we cannot forgive someone for their wrongdoing against us, but we expect that God will forgive us for our sins which are worse than what anyone can do to us, then we are full of pride,
to grieve is not evil, and is not the cause of withholding forgiveness in any case. a parent will grieve over the loss of their child whether they died by the hands of a murderer or if it were by a sickness, but they withhold forgiveness, even without recognizing it, by pride,
since it is a sin not to forgive, and all sin is rooted in pride, so how can we say it is not pride? it may not seem like pride to those who do not know the vice more deeply, and i can understand how others would see it as absurd that anyone could call it pride when a parent refuses to forgive a murderer for killing their child if you see pride simply as an inordinate feeling of honour and self-respect, then i can see why you disagree, but i am not speaking of that kind of pride, i am speaking of the idea, as i already said, that somehow this crime is to great to be forgiven, which is not true, it is pride because it is a lie,
but remember i am speaking of the willing decision not to forgive, not simply ill feelings, but the actual choice.
grief does not stop someone from forgiving, you can forgive someone and still mourn the loss of your child, lack of forgiveness comes from a lack of virtue, or more specifically, the lack of charity(which is the love of God for His own sake, and the love of neighbor for the love of God) and the lack of humility(which, contrary to pride, is the virtue of truth)
the direct refusal to forgive is a sin, there is no question about that, but then the question remains, what sin does is fall under? or in other words, what vice is it rooted in? all sins are rooted in one vice or another, and all stem from pride, so while the refusal to forgive may be from another vice, such as anger, it is still from pride, since anger also stems from pride.
but perhaps it would be easier to understand if you look at it this way - it is not so much the degree of pride that causes one to refuse forgiveness, but the lack of humility and love...we are told that "one of the surest signs that men are children of God is in their willingness to forgive injuries and sincerely love their enemies, because in loving our enemies there shines forth in us some likeness to God our Father, who, by the death of His Son, ransomed from everlasting perdition and reconciled to Himself the human race, which before was most unfriendly and hostile to Him" - catechism of trent...
it takes alot of grace and virtue to forgive something as heartbreaking as the death of a child, but knowing that it is good and the will of God to forgive our enemies every wrongdoing, then we also need to ask for the grace to forgive, it's not something you can do on your own, it is hard, but it can be done, and to refuse to forgive so much that you would even refuse Gods grace, is most certainly pride,
it is a touchy subject yes, but very many parents have lost their children by the hands of another, and God has not given an exception for them, they are obliged just as anyone else to forgive, even if it's very difficult, they must ask for help...
well, sorry to make this so long, but i hope it helps, take care.