It seems more like a move to control their own software licenses. If a device isn't licensed to run GApps, then why should it be allowed to use the services?
And from another direction, if a manufacturer refuses Google's terms for including the software, then why should that manufacturer get the benefit of being able to include the software, outside of its licensing terms?
And from another direction, if a manufacturer refuses Google's terms for including the software, then why should that manufacturer get the benefit of being able to include the software, outside of its licensing terms?