Importing collada (.dae) files makes no sense?

Hello together,

I have got an issue with Unity3D. I want to import the geometry of a robot. The file-format is .dae (Collada). I can either drag&drop the file into the Project-browser or do a right click and then "Import New Asset". That works perfectly. But what I'm concerned about is that when is drag that imported geometry into the Screne-editor it's is a 100 times bigger then it was supposed to be. So I went through all the settings in Unity3D to find a solution. So when one selects the geometry in the Project-browser there are 2 significant settings. . The first one is the scale-factor. With that setting I can perform a little work-around. I just have to type 0.01. But then there is the question: why would sombody make it so difficult? The next setting says that units will be converted from millimeters into 0.1 meters (so decimeters). But why??? What sense does that make? And why is there no way to change that setting? So I went though the code of the .dae-file and at the top of this code I found the following declaration:

 <?xml version="1.0" encoding="UTF-8"?>
 <COLLADA version="1.5.0" xmlns="http://www.collada.org/2008/03/COLLADASchema">
     <asset>
         <contributor>
             <author>W.E.S.T. GmbH</author>
             <author_email>info@west-gmbh.com</author_email>
             <authoring_tool>WestUniversalConverter WUC v1610100855</authoring_tool>
             <copyright>W.E.S.T. GmbH</copyright>
         </contributor>
         <created>2018-09-07T11:54:29</created>
         <modified>2018-09-07T11:54:29</modified>
         <unit meter="0.001" name="mm"/>
         <up_axis>Z_UP</up_axis>
     </asset>

It says that the unit of the data in that file is 0.001 meters and that this again is called millimeter. So that is correct. Then again, why would Unity3D mess up the units? I experimentally changed that number from 0.001 to 1.0 and went back to Unity3D. What happend was that the text changed from "1mm to 0.1m" into "1m to 100m"??? This makes totally no sense at all? Please, could somebody explain that to me and more important give me a solution other than changing the scale factor, because I already know.

Best regards Leon