You are right about a lot, but that's not how I would put it at all. Scirra are a small company, and they simply don't have the time to write all of these exporters. However, the public demanded mobile export and they were given mobile export. Yes, it's a bit dodgy as it uses such a young technology. But the option's there.
I do agree that Scirra should have been more careful with their advertisement of features - it's easy to believe that they offer full export. I'd much rather all the mobile exports be rebranded as 'experimental' as essentially that's what they are.
Regardless of their advertising choices (any larger company would have done the same in a second), Scirra have spent good time making a user friendly product for beginners and prototypers. There's no need to complain as AFAIK they have never said you will be able to create AAA apps and programs right out of the gate. You can, but it will take effort and time. It's never been said that other engines can't export better native apps. They also take much longer to make and are more tedious to program. It's your choice.