I think what they're trying to say is that they are abiding by the general principle of not allowing apps that duplicate built-in functionality, because they fe

I think what they're trying to say is that they are abiding by the general principle of not allowing apps that duplicate built-in functionality, because they feel it might negatively impact the user experience of their product. This is a much more defensible (and I think probable) position than that they are singling it out for purely competitive reasons.