I have forgiven him. As far as I am concerned this is trivial. But unless he apologizes then he will have to deal with it before the Lord.
The Bible says that we will have to give account of every word we have said and written.
36 But I say unto you, That every idle word that men shall speak, they shall give account thereof in the day of judgment. 37 For by thy words thou shalt be justified, and by thy words thou shalt be condemned.
Matthew 18 also tells us that it is our responsibility to go to those who have trespassed against us and tell them their fault. You don't get to ignore that.
Now if I was the only person who knew about this then I can forgive him and that is that. But he posted this online in a public forum, therefore it is not simply up to me.
I have a responsibility to tell him his fault, if he refuses to listen, well then that is on him.
It is stunning to me how many in Christianity have such a poor grasp on the word of righteousness.
15 Moreover if thy brother shall trespass against thee, go and tell him his fault between thee and him alone: if he shall hear thee, thou hast gained thy brother.
If this conversation had been on a PM then it should be handled on a PM, but if it is on the forum it should be handled on the forum. But Jesus is telling us to tell your brother his fault, that is not optional, that is a direct command from the Lord.
16 But if he will not hear thee, then take with thee one or two more, that in the mouth of two or three witnesses every word may be established.
He made a claim, I asked for him to provide the post as a witness to confirm his word. This request is according to the Lord's word here.
17 And if he shall neglect to hear them, tell it unto the church: but if he neglect to hear the church, let him be unto thee as an heathen man and a publican.
This doesn't mean that you don't forgive him. If you have unforgiveness in your heart it will grow into a root of bitterness. This chapter concludes with the Lord telling us that we should forgive others because the Lord forgave us. There is no excuse to not forgive. However, there is also no excuse to not address this head on and tell your brother or sister their fault.