I’m afraid being tactful frequently involves a little bending of the truth. Lying simply being wrong is a little oversimplified, that’s all. And it’s not a lie anyway, when there’s multiple reasons for something and you give one, that is not simply a lie, except by omission if you were expected to thoroughly explain yourself.
I see no such standard here. It’s just politics, which is messy. I’m sorry if it doesn’t live up to your lofty standards for museum curator honesty and disclosure.