Do we even know whether the EuroVelo3 trail, to the extent that it overlaps with the
Camino de Santiago trails, got EFDR funding or similar EU funding? EuroVelo is a European cycle route network that has been initiated by the European Cyclists' Federation. Just because the EFDR logo is on the Federation's website doesn't mean that funds were made available to them in northern Spain. I checked and saw that they gave some money to the development of northern sections of EuroVelo 13 – Iron Curtain Trail - it goes through AT, CZ, DE, EE, FI, LT, LV, PL but not ES (Spain).
In forum threads, posters present all sorts of arguments or own ideas why one group or the other group should not walk or bike where another group is walking or biking for that matter. Comments find approval from other posters or are refuted.
There is no decision-making power here on the forum: Spanish traffic law and additional regional or local regulations decide who is allowed to use roads of any kind and other ways and paths of any kind in Spain and who is prohibited from use.
As far as I can tell, there is not even much lobbying with Spanish townhalls or provincial authorities emanating from our forum threads.