Hello.
No personal feelings about this, we just go with community decisions.
Most non-locals are confused because the "métro léger" name is misleading.
One the reasons is that several parts of lines M1 and M2, sometimes entire streets, are shared with cars, like Rue de la Station in Anderlues.  It fails at the first question according to this decision tree: https://community.openstreetmap.org/t/railway-light-rail/69578/34  We find comparable situations in Antwerp and Brussels and all of them are trams, because they all have the same problem: some parts of the lines are completely mixed with traffic.
Even LRTA, which maintains in inventory of networks they consider to match the LRT criteria, does not consider it as a light-rail: https://web.archive.org/web/20191027053236/http://www.lrta.org/world/worlda-e.html
Another issue to consider for OSM: the data model seems incomplete for light_rail.  Stop position nodes and crossing nodes do not match the same tags.  And it would be impossible to map M1/M2 as light_rail while keeping M3/M4 as trams, the platforms and tracks are shared.  Can you point to some documentation explaining how those points could be solved?