How do you know if your birthday isn't in some publicly accessible government database somewhere? Did you try to find it? Did you hire a private investigator (who has quick access to all those databases) and ask them if they can find your birthday?
If it's true that that information is out in the wild now, then I expect government to tighten their tech security procedures.
How do you think the RNC got birthdays for 200 million Americans in the first place? Public records. 200 million Americans are NOT affiliated with the RNC.
As I replied elsewhere, there is a market for reselling your information on the internet. In some cases that is legal, and in many it's probably not. As a tech person you should know this.