So I need to RANT because if I don't I'm going to lose my mind

So I was raised by my step dad for 13 years of my life. Called him dad and still call him dad but here's the thing. My little sister (his biological child) just found out that his new wife just had his baby, before that found out he gout married and has a new step son.. my problem with this is that he has completely cut us off from his life. And it hurts me. He got medically discharged from the army years back and moved back home because he had cancer and the last time I saw him I was 15. He doesn't call us or tell us happy birthday (or any holiday) blocked my little sister from Facebook. His flesh and blood! And our grandma (his mom) messaged my sister telling her the wonderful news of him becoming a father again.

Is it wrong of me to be so angry about this? Like where was all of the love he seems to have for his new fucking family when me or my brother graduated high school, or the joy of my sisters volleyball games! Or my marriage, or my baby... he complete cut us out of his life and literally is in a state next to us.. all I have to say is have a nice life and fuck you and your new family. I'm done hoping one day you'll tell me you fucked up.