A statement P about a single element in a dual or multiple set does not seem to logically exclude P applying equally to other elements in the set; yet we often talk as though "P is true of X" implies "P is not true of Y (or Z)", when X, Y, and Z all belong to some grouping.
For example, take "Men work to support their families". Does this logically imply that women do not work to support their families?
What about "African Americans suffer from discrimination"? Does this logically imply that Asian Americans, Hispanic Americans and white Americans (among other racial groupings) do not suffer from discrimination?
Such objections are often raised in discourse. Given (x, y), "P is true of X" is thought to imply "P is not true of Y", or "Not-P is true of Y". If there is no logical exclusion above, what are these objections targeting? Is it a question of salience, rather than logic?
Thank you for your good question! Answering questions of this general type has been a big concern of the field of philosophy of language for the last few decades. One way of starting to understand where this tradition is coming from, is to distinguish between the literal meaning of a sentence, and the meaning that a speaker using that sentence is normally thought to convey. So suppose that you often has unkempt hair. One day you show up with nicely combed hair and I remark, "Your hair is combed!" Now it will be natural to take me to be *suggesting* that your hair is normally not tidy. But this is no part of the literal meaning of the sentence. If it were, then I'd contradict myself by saying, "Your hair is combed, though of course it is normally tidy." This might be an odd things to say, but it isn't a self-contradiction like, "Bob is a bachelor, but he is married." So we can distinguish between what a sentence usually means and what a person uttering that sentence might be conveying,...