It would have been harmless if they shared but they specifically knew not to. You both asked them to respect your wishes of privacy and they didn’t. They are in the wrong.
You're not overreacting. They're clearly wrong and know it too, they just need to twist it on you so they're not seen as the bad ones. Moving forward they unfortunately find out important news at the same time as everyone else. They clearly can't be trusted to know beforehand.
Usually just say this news once you know the gender not earlier, even when I wanted to share during the NY my father told me just keep to yourself and tell us only once it is actually visible and you have got a belly. People don't care, they want to share, it is happiness, but in the future if you have the 2one, just keep it to yourself and share when you are ready, not immediately 🥰wish you all the best and lots of love, take care, very exciting moment for you