I agree with you that the real reason for it is EEE but their justification for it is that for enterprise and corporate customers, the only ones they care about, they can't control Firefox in the same was as they can Edge or Chrome with the Microsoft Account add in which allows the MDM agents like InTune to apply DRM. Their primary concern (so they claim) is the enterprise administrators ability to control the computer, provide settings, configure defender xdr security and all the other bs products they sell.