While it may be fun to denounce, we have to always try to be most effective; and in this case, there is such a mountain of cold fact to employ, why give up any part of our advantage, for self-satisfaction.
You get it.
Voters generally tend to focus on the POTUS candidate, and ignore the VP guy. (Unless VP candidate grabs spotlight-—refer to Sarah Palin.)
Floating rumors that Hillary is dying —true or not —will just push Kaine into the spotlight.