Why show any information at all if it isn't complete?
For example, the app I have, I wrote a capabilities profile for. This capabilities profile knows all, it is a swami. It queries the device and finds if the codecs are supported easily.
We went through dialog with users and came up with detection to support these codecs.
see here: https://emby.media/community/index.php?/topic/62070-issue-with-watching-in-progress-recording-on-roku-tcl-tv/?p=616551
Now what we do is show the user nothing on what can or cannot play. The app will transcode when it has to, or when the roku throws an error or the video player closes, the app is smart enough to sense it cannot direct play and falls back to transcoding. Now I know the RMP app cannot do this. But it can remove that part about what can or cannot play. It doesn't need to show this information if it isn't accurate. If I put RULES up in my house and don't have enough room. We just don't list some of the rules. People then break the rules not listed and wonder WTF? We say, dude.. there is only so much room to display the rules, plus different people get different rules, those are the most common rules that apply to everybody. When you break a rule not on the list, we have to explain why it isn't on the list everytime. It does get tiring, but we explain the room isnt there to show it all, all over again. Over time, people stop listening to you about the rules and make their own lists. This is what I have done with Roku. Stop listening to them. You can't listen to people who aren't forthcoming. You can't listen to roku on this subject. That is unfortunate.
Like you say, they need to make that trickplay section where it lists the codecs as the defacto, what can roku play. Then put the little caveat asterisks * by the codecs which arent supported on every model saying so. It isn't that hard. Is roku just 4 guys in a garage? Then it might be hard. But they aren't. It is ridiculous here we are 2018, and the company is shying away from actually giving accurate information. Odd right?