I thought the reason why iOS blocked both SMS apps and Keyboard apps is because they wanted to ensure rogue app developers aren't invading your privacy and/or spamming (e.g. key loggers or sending SMS you didn't compose).
I get why the developer might be ticked, in this case, but I still think it's a stretch to speak of "cloning" a very very basic QWERTY keyboard, and the breathtakingly-original concept of putting a keyboard onto a touchscreen. /s
As if that is some kind of grand-scale theft of intellectual property. Please.