Noticed this too. While I use the mirrors when driving, it's still hard to see the monitor when backing up. I'm guessing Newmar thought it would be better to angle it at 90 degrees so the passenger can see it too and keep an eye on things
In any case, I searched for angled mounts with no luck. The monitor is only 1.25 inches deep according to the specs I found. Maybe remove the monitor, cover the hole with something and bolt an external articulating mount? Just musing out loud.