It is very unusual for companies or organisations to deny being accessible. In much of the world accessibility is a legal requirement, but it is very rare that it is precisely defined. So it is a very different matter whether that accessibility is adequate.
If the author had been in a chair, they would likely have found that the ramps up to the dais are far too steep, and require them to be manhandled up in full view of everyone. Some ramps may have been temporary and split, preventing powered chairs from using them. Or the ramp might have been ostensibly owned, but misplaced when it comes to be needed. They may well have discovered that the only accessible bathroom is in the bowels of the building, frequently used for convenience by nondisabled people, require a key from reception, is used as a store room, or is part of a regular bathroom behind an inaccessible automatic closing door. Were gradients in the outdoor landscape too difficult? Could all the doors be opened while having hands on both wheels to move the chair? Were refreshments accessible? Were tables the right shape to get a wheelchair under them? What about a powered chair?
I completely agree and sympathise that the range of disabilities is much broader than physical disability. But I think we should be careful of assuming even physical disability has been cracked. I think it is essential that more people have experience of navigating space in wheelchairs. In my experience it is much much more difficult than I would ever have assumed.