This is true; it's very confusing to me why people insist that useless labour counts as valuable. Neither Adam Smith nor Ricardo and certainly not Marx actually held a labour theory of value in which objects which are not firstly of demand are valuable. Not only that, but the theory doesn't even attempt to draw normative conclusions about whether the theory is just or not.
My advice is that if one is going to talk about political economy (or the history of economics) then one ought to read the text themselves rather than assuming caricatures as if the proponents of such theories were truly idiots. Smith, Ricardo and Marx were extremely intelligent people.
The line being discussed in this thread can be abstracted to the question of useful labour in the LTV; if we are discussion the LTV then we are discussing the theory which was advanced by the Western European political economists, and the objections which they countered or in some cases didn't counter.
At the very least, it seems ignorant to discuss a theory while not taking into account the established literature on the topic.
My advice is that if one is going to talk about political economy (or the history of economics) then one ought to read the text themselves rather than assuming caricatures as if the proponents of such theories were truly idiots. Smith, Ricardo and Marx were extremely intelligent people.