Mate, what on Earth are you talking about? A private DNS server that can only be hit by clients on an internal network, which differs from public DNS, is split horizon.
https://en.wikipedia.org/wiki/Split-horizon_DNS
I could not have been clearer that the private DNS servers I use provide different results from public, for the same names, which is the split. Not all private DNS servers are split horizon, and nothing I wrote implies that that's my understanding. If that's what you've concluded, then you've either failed to comprehend what I've written, or you're a troll.
But at least we both agree private dns =/= split brain. :)