But this is not related to licensing: anyone can offers support for any piece of software and, as far as I can tell, there is no way to prevent that in a licens

But this is not related to licensing: anyone can offers support for any piece of software and, as far as I can tell, there is no way to prevent that in a license. Otherwise Oracle would have eliminated Rimini Street years ago (the only thing they got is $90M in the recent lawsuit which is almost nothing).