The transparency of this information is a public good in itself, so it is in the interest of the public that this information can be requested as freely as possible.

Of course there should probably be a way to limit waste, but putting all financial cost onto a single person is a way to effectively limit freedom of information to the point where it contradicts and undermines the whole idea behind it. That's one of the reasons why this change is being proposed, and it is not a stretch to call this nefarious.

If you design processes to be open by design, the cost of extracting data (removing sensitive data that is indeed not needed) goes down radically. Governments know this and resist it.

Yes, it is costing the taxpayer. However, I think there needs to be some cap, because otherwise the government can weaponize that and be extra inefficient when processing requests for things they don't want to become publicly available.

The current cap of 500€ is a good compromise IMHO: It deters people from issuing unnecessary FoI requests while at the same time keeping it in reach for the average person if they really want that information.