All you're doing by saying "ad hominem" is shifting the focus to technical delivery of the argument rather than focusing on the real matter of the discussion.

All you're doing by saying "ad hominem" is shifting the focus to technical delivery of the argument rather than focusing on the real matter of the discussion. I'm not sure I agree. The use of ad hominem is the shift away from the discussion proper. Calling ad hominem (or any logical fallacy) out is merely a recognition of that shift, and could be considered a (weak?) attempt at getting back on topic. When used correctly, that is.