To recap - Doctor Breen sold out earth for subjugation to the combine, but the alternative is total annihilation. Instead letting earth be wiped out, he believes in his ethos of bettering humanity by molding them into an heteronomy image of ant colony working in hierarchy, using this to justify appalling acts similar to unit 731. He has an uneasy alliance similar to that of Jewish collaborators in WW2, where he himself is condemned but in a position of authority.
His patronizing 1984 news bites emphasizing the will of the state, Combine beating up, attacking, shifting people like cattle are now more relevant than ever thanks to Mr Trumps hair piece warning us the dangers of magical thinking.
In many ways the threat of Gordon Freeman could justifiably end humanity for the sake of satisfying human dignity rather than yielding for the sake of existence itself, which he eloquently explains in the later final section of the game.
Aesthetically he is a generic old looking man, intelligent with slick presentation, rather than a man with disfigurement, mental issues or a women dressed like a bad S&M party. Nothing about him suggests cynism, like a politician it's his job to win the people over through well rehearsed rhetoric.
Do you think this generation will ever produce a villain so well executed as Dr. Breen, from Valves undisputed masterpiece? So far it's looking not to be the case.