This is appalling behaviour. I have escalated it to be told:
With regards to your claim for the IHG promise, I would like to explain that this applies to operational hotels that cannot honor guests reservations. This could be due to overbooking, wrong inventory, errors on the website/central reservation or hotel staff errors. As the hotels closure is due to the current COVID-19 situation we are still going through, we can not classify the cancellation of your reservation in any of the reasons I mentioned. I apologize that this has not been elaborated on the published IHG Promise online, however I will note your comments through this case to the department in charge of our website announcements. For this reason I regret that I cannot provide a confirmation number to relocate you to another comparable hotel as the hotel noted that they will not be able to compensate.