Hi Mathieu,
I understand you care a lot about this topic and are posting about it in many places but I have a personal rule that a lot of the people in Wikidata know. I am willing to discuss and explain basically anything on a calm and rational basis. (And I did this on-wiki I believe.) The rule is simple: The more loud, aggressive and pushy someone gets about a topic the less likely I am to engage. This rule has a simple reason: I don't want Wikidata to get into a spiral of shouting. If we do this people get into the mode where only if they shout they get heard so they shout all the time. This is toxic for a community. So I fear I can't contribute to this thread beyond this message.
Cheers Lydia