Am I overreacting?

Long story short: We told our families before our baby was born that we want visitors to have a whooping cough vaccine and not to post our kiddo on social media. Found out months later that my sister-in-law had pictures posted on Facebook days after our baby was born and my brother was tagged in them (we are not on Facebook so a friend had told us). She claimed to have not known and took them down. But, when I talked to my brother about it, I asked if we had talked about it (maybe I forgot?) And he said that we did talk about it and he knew not to post pictures, but that he didn't agree with my rule/boundary regarding my kid. I'm livid. I was questioning myself thinking maybe I forgot to tell him, which would be my own fault. But he knew! I know he's not the one who posted them, but he was tagged in them because his wife posted them and the pictures were on his Facebook, too. I don't know if he thought this was a loophole, but I'm so angry! And to boot, he's not even remotely remorseful. Just doesn't agree. He also said that I was asking for a lot in my pregnancy so he was just saying yes to everything while I was pregnant, which is hurtful and makes me question other boundaries they don't respect. I'm just hurt because I trusted him and thought he'd not only advocate for me, but for the baby, too. And it's oddly caused a lot of drama with both my brother and sister-in-law to the point where we aren't speaking. I figured we would talk about it..."sorry I forgot" or "my bad" and then we'd move on. Am I overreacting? I'm just trying to do what I think is best for my child and these were the absolute last people I ever expected this from. Sorry for the novel, but help!🤷‍♀️🤦‍♀️