While the leak UpGuard discovered seems bad, in reality, things aren't really as you'd imagine them. US voter registration is often made available to private entities by US states, some of which consider it public information.

This is what allowed the growth of a special niche of companies that provide so-called voter advertising, allowing campaigners of various political camps to go after registered voters with targeted ads.

Additionally, after the first leak (191 million, December 2015), most of the US voter registration info has already been sold and traded on underground hacking forums and Dark Web markets. If US citizens like it or not, their data had been exposed online a long time ago, and they'll never put the genie back in the bottle when it comes to their personal details.

[Rebecca Schaeffer] is rolling in her grave FFS.