Why are they suggesting that lack of documentation is a good thing?

They should hire someone to study the beavers and their work. It could be useful to other countries.

According to AOPK spokeswoman Karolína Šůlová, beavers have contributed positively to water retention in other areas in the past. However, it occasionally happens that what suits them is not in the interests of humans. For example, in the vicinity of Lanškroun in the Orlickoústec region, beavers inadvertently flooded fields and waterlogged a nearby railway line.

Yeah, that's why you need this shit studied and documented