I was wrong. On further reflection, this is a failed attempt to refute this point, though I don't think the ensuing discussion of Kant actually gets to why.

If you're familiar with the definition of bachelor, then this statement equates to, "There are no unmarried married men." Any statement of the form "No A are not-A" is completely uninformative. As it can be decided a priori for any consistent value of A, stating it demonstrates nothing.

If you aren't clear on the meaning of bachelor, then this statement would require a citation of the definition in order to be convincing. This would constitute supporting evidence, and it would serve to demonstrate the meaning of "bachelor."

Thus, this does not go to refute the claim that an assertion without supporting evidence demonstrates nothing, as that is clearly the case here.