I'm going to throw down some thoughts.
Tolwyn is a traitor because he killed/engineered the deaths of thousands/millions of Confed citizens. These are the people that he, as a serviceman, has sworn to protect. Therefore regardless of his intentions he is a traitor and no longer a hero.
Does anyone wonder why Tolwyn would think that a genetically tinkered human race would be more likely to survive than humanity as it currently is? I mean if he was successful and humanity becomes based on a few 'superior' genes, wouldn't that make humanity more susceptible to a new type of disease or other biological weapon? After all his own gen select device could be re-calibrated specifically to attack those genes he thinks are the best.
Finally what makes Tolwyn think that humanity as it is, is unlikely to survive another war? It is undeniable fact that Confed won the Terran Kilrathi War. You could say it was a fluke. However others at this board pointed out that at the beginning Confed had a bigger fleet than the Kilrathi. At McAuliffe the Kilrathi managed to even the odds but this could easily occur to a genetically tinkered race. Secondly before the False Truce Confed had gained the edge - a more determined/aggressive government would've seized the initiative and defeated the Kilrathi soundly without recourse to last ditch attacks like Big B & T Bomb. Confed getting tricked at McAuliffe & at the False Truce negotiations demonstrate weaknesses/deficiencies remedied not with genetics, but with modifications to priorities and tactics.
As a leading admiral how could Tolwyn not realize this. If anything, Confed's survival for 40 odd years of war, and our staving off the Kilrathi armada in the BoT, despite serious handicap, proves that humanity is no push over. This is further reinforced by the fact that a hardened warrior race like the Kilrathi were unable to achieve a decisive victory for so long, despite having the 'right pyschological disposition,' cloaking devices and a willingness to use biological weapons.