I agree that we shouldn't go the Danzou route and take the hard decisions because they're hard, without thinking about whether Machiavellian schemes are actually the best way to achieve our goals, but I also don't want us to shy away from Machiavellian scheming if it is the right way to achieve our goals.
There's also a meta-problem of whether we can trust ourselves to make the decision properly in the first place, with the other option being to put in categorical refusals to take Machiavellian options if we worry that we might do a Danzou and think that a Machiavellian option is better without it actually being so, but the cost for that is that we shut ourselves out of taking Machiavellian options when they are better, and depending on the situation that could spell the difference between game over and victory.
(Also I know Machiavellian doesn't fully encapsulate the kinds of actions we're talking about here but it's more streamlined than a five word hyphen train)
Hazou compromising his own ethics makes me leery too, but only because I need to keep an eye out that he doesn't take it too far, or do it in the wrong place. The overall sentiment of the situation, that if our goals are already this hard to accomplish then if we try to achieve them without any moral compromise we're even more likely to fail along the way, is one that I do agree with since this isn't a nice world and our ambitions aren't small.