Too dangerous to be left alive
When anie kills count dooku palps says that he(dooku) was too dangerous to be left alive. When Mace wants to strike plaps he also says tha same thing. Obi-Wan would have stopped anie from finishing dooku if he were conscious so it IS the Jedi way not to strike the defenseless wich means Mace had issues with the dark side and that he is no better than the Sith.