Not absurd at all. It's their money, their property, and there are multiple reasons why they may not wish to publicly show them off like that.
1) It stops people from being able to replicate these things, then passing them off as genuine when they are not.
2) Their collecting is their personal hobby, and so they wish to keep their private lives, you know, private.
They are also under no obligation to show their private property to anyone, regardless of how much of their money they spent on those things. In fact how much they paid is entirely irrelevant really. To think otherwise, strikes me as a feeling of real entitlement.
You're new here, so clearly haven't been around long enough to know this, but quite a few members here own very rare film/tv props, that they don't show off here. Brandon owns the actual V2 saber prop and restricts how and when it has been publicly seen, as is his right. Of course other respected members have seen it, held it, and even measured it, but that was entirely up to Brandon.