And here we go...
Sounds kind of like favoritism for the way you want to play and use the system if dock-only undermines it but portable-only doesn't.
Not really. Right now, Nintendo's main PR spin is that the Switch is more than just a home console, it can also be used for gaming on the go. Thus, having some touch-based games available to be played in handheld mode
strengthens the selling point, because it's something you can't do with other systems. However, a dock-only game
removes the main selling point, because then you'd have a game that's probably already on other systems...and since it's not portable, there's really no reason to get it on the Switch unless it's your only console.
As I said in the rest of the post you quoted, dock-only games wouldn't be a problem later on in the Switch's life, because hopefully by then there would be enough games to where the selling point of "console that can be used on the go" doesn't need to be pushed so hard. Because the basic hybrid concept is now understood by the public and backed up with a solid library, Nintendo could then expand the hybrid concept and throw graphics/power-focused devs and home-only players a bone by allowing, and making a push for dock-only games. But for now, dock-only games only muddle the messaging and give the detractors more (and legitimate) fuel.
It's somewhat similar to how GBC-only and N3DS-only games came out later in those systems' lifetimes, or how the Micro and DSi dropped GB/GBC (Micro) and GBA (DSi) compatibility when they were released. What's important at launch isn't always as important later on once the library's strong. Touch-based, portable-only games is something Switch can do that PS4 and XB1 can't, so it's good to have them there from the start. Dock-only games are not only something that PS4 and XB1 can do, but they can do it better than the Switch. As such, it's better to wait until later to start making those, once there's enough dock/portable games to make up for a few dock-only ones. Also, a hardware revision could come into play later on.
And at the end of the day, I don't see why we should be concerned about "mixed messaging" with portable-only games when
Nintendo themselves haven't really made a big deal of them, or the touchscreen, at all. Their launch messaging has been pretty clear.