مَا زَيْدٌ إِلَّا قَائِمٌ
Zayd is standing, not the opposed alternative.
For qalb, the listener must affirm an alternative opposed to the speaker’s intended attribution in the relevant discourse. Standing versus sitting can establish such a contrast; writing versus poetry may not always be mutually exclusive.
Therefore not every exclusion is reversal. Where the competing qualities can coexist, one must examine whether the utterance rejects combination or specifically rebuts the listener’s claim of the opposite.