DefaultBindableProperties.GetForCommand: why does it break for "Xamarin.Forms" types?

[kswoll]

If you look at the implementation of this method, you'll notice that it breaks if the type name starts with "Xamarin.Forms":

internal static (BindableProperty, BindableProperty) GetForCommand(Type bindableObjectType)
{
	(BindableProperty, BindableProperty) commandAndParameterProperties;

	do
	{
		string bindableObjectTypeName = bindableObjectType.FullName;
		if (bindableObjectTypeDefaultCommandAndParameterProperties.TryGetValue(bindableObjectTypeName, out commandAndParameterProperties))
			break;
		if (bindableObjectTypeName.StartsWith("Xamarin.Forms.", StringComparison.Ordinal))   // <---- Here
			break;

		bindableObjectType = bindableObjectType.GetTypeInfo().BaseType;
	} while (bindableObjectType != null);

	return commandAndParameterProperties;
}

I do not understand the purpose of breaking here and in fact this actually means that a class such as ToolbarItem breaks when using BindCommand. This is because the command and command parameter properties are actually registered for its base class MenuItem. If this line were removed, it would presumably work on the next pass in the loop. But because it is there, it throws the exception at the call site since the returned command property is null.

Furthermore, it's not possible to manually register the properties via RegisterCommand because these properties are already registered for MenuItem (where those properties are defined).