Am I really being unreasonable for not wanting to forgive my absent father and his mother, despite my mum begging me to

My father has been absent from my life since before I was born, infact he and his family (mainly his mother and his other brother) denied being responsible for my mother's pregnancy then. His mother flat out refused to accept my mother despite pleas from her family and even our churches (they attended the same church).

They called my mum a gold digger because my father was rich then and he was also the only breadwinner of the entire family, so I guess him getting married was going to ruin that as he would have other responsibilities.

They cut all contact with my mum, even going as far as changing their surname so I wouldn't have the same name as them. Once when I was about 6, I begged my mum to take me to him. It was a weekend yet he barely hugged me before lying about some work he had and then he disappeared the entire day( I got there around 8am and left by 6pm) yet I didn't see him. Neither did he call, and so I completely zeroed my mind from contacting him ever.

Now after 20 years of radio silence, his mother and brother suddenly contacts my own mum, kneeling down to beg for forgiveness. She said that ever since he abandoned us, he lost everything and isn't rich anymore. He even had to move back to his parents house with his wife and kids(he remarried and had children). So now he and the entire family wants to beg for forgiveness and also wants my mum to pray for him so that he'll be able to move on and get rich like before.

My mum on her part has never said anything bad against him to me because she really loved him so she already said she's forgiven him. But I can't because I don't even know him, If I passed by him in a crowd I wouldn't even recognise him. Now my mum is begging me to forgive him, she hasn't told our family about this because I told her not to and I know I'll be pressured to forgive him if they know.

I do not want to forgive him and I don't want to talk to him at all