edit: I pieced together information from other comments and noticed that who one voted for is not available, even through this breach. That's great. My comment here was addressing the breach as it was presented in this comment thread.
I assure you there are already databases of every registered voter in America. You're not allowed to do certain things with some of the data, but its always been available.
That's an interesting and subtle point, to which I don't know how to respond fairly. My information on these laws comes solely from the article, which says:
> In California, information on voter registration cards is considered confidential, and subject to many restrictions to access and use ….
"[S]ubject to many restrictions" links to https://www.lavote.net/Documents/purchase-order-for-voter-el.... I suppose that you could argue that these restrictions do not prevent you (assuming you are a US person) from accessing the data, but I think that the data are far from being public, which is what I understood you to be saying.
I think that this is a very important point. It doesn't matter how important it is to you that my information is public; the seriousness of its exposure depends on how important it is to me. (I am using 'you' and 'me' here not to argue with you specifically—in fact I agree with you!—but rather as generic pronouns.)