From a human perspective, I absolutely understand wanting your loved one and even strangers to have their dying wish when it comes to food, bc why not? But, from the health facility's perspective, they probably can't monitor every request and determine if it's safe for that specific patient or not, for legal and practical reasons. Maybe they could if they really, really wanted to. But I imagine, for legal reasons, they have pretty cut and dry policies.
In that situation w/ the guy needing thickener in fluids to swallow, they'd end up having to parse each patient's record & decide whether that specific food was ok or not, all while teetering on the edge of avoiding lawsuits for premature death, even though they're about to die. If that guy choked to death on that soda, you can believe his family could sue for the health facility killing him prematurely. And it wouldn't be you, who bought it, on the hook in that lawsuit--it'd be the healthcare place he was in. And so the nurses are trying to avoid being fired, bc if the facility says they did something that could endanger the place legally, their job is gone.
As inhuman as it seems, and it does seem inhuman, I do get why they have policies like that. Maybe there should be a better way to grant people their dying wishes, on a human level, bc it is sad.