Honestly, it could have gone either way, and it very nearly did go their way. The Globalist agent did point out that the T&Cs say: The best room available will be determined by the applicable hotel or resort in its sole discretion and may vary from stay-to-stay.
Which technically gives any hotel a complete out from providing any upgrades but isn’t really in accordance with the spirit of the benefit and I imagine is there as a CYA for edge cases.

Ultimately, the agent did agree that I should get the suite and was kind enough to advocate for me. But yeah, it took about 30 minutes of my and her time.

And agree with your assessment - gross.