That option is not available to me. I switched to 720 HD (that's the best they offer) and the text still looks broken like before.
It's YouTube; you were probably viewing in 480p30. My pop-up notice says to view in 720p60 mode, so that you can see the interleaved graphics.
Once you view in 720p60, the Harmony's menu looks incredibly legible via RGB, unlike viewing in RF where I have to strain my eyes to see what the heck is going on.