They may indeed show that one can construct Frankfurt-type examples that explicitly presuppose indeterminism in which there are no alternative possibilities.
These presuppose a reference mass consisting of all possible instances and their use can be interpreted, under appropriate circumstances, to entail a ‘universal’ statement about all instances.
Your argument seems to presuppose that it does.
But individuality and distinctiveness presuppose coherence and unity: without them, nothing can stand on its own as an object either of admiration or contempt.
Since the reverse is not true (actuality does not in the same way presuppose potentiality), an actuality is prior in definition to its correlative potentiality.
Mental predicates therefore presuppose the mentality that creates them: mentality cannot consist simply in the applicability of the predicates themselves.
We do not, of course, presuppose that nowhere ever is there a failure of, say, vision.
The guidelines for human behavior that have their source in the Bible presuppose universal applicability.
But, of course, it does not presuppose that all speakers understand the word this way, only that they can if they think about it in a certain (fairly common) way.
Such an argument would have to presuppose that there is somehow something wrong with being gay.