The dad still said happy birthday and I love you only to get that text back. Older folks are exposed to a lot of propaganda and many are brainwashed (the hint in this case is the "God bless you"). Without more context I'm hesitant to call him an asshole.
Based on this small exchange I'd be more inclined to say they are both assholes.
It's just sad that they can't look past this and love each other regardless.
So you think its OK to send a unsolicited pic of your genitaila, to your dad, given that its because he misgendered you?
Anyone sending unsolicited pics of their balooga, is never OK... In fact. It could actually be a crime. Neither of you come off well in this interaction.
I seem to be getting a good number votes in both directions, to those down voting me, do you think unsolicited cock/pussy pics are OK? Cus if you do, you are the problem. The dad is a bigot and need to correctly educate himself, but OP responded in a way that is disgraceful. They are both deplorable.