I assumed tester was making the (ever so slightly hair-splitting) point that Machiavelli was a Renaissance SPAD, not a political leader, and that it's more appropriate to call Cummings Machiavellian than Bojo.
Machiavelli is not the prince any more than Frankenstein is the creature. It's not a perfect analogy, since calling the behaviour "princely" is pretty vague unless you specify that you're talking about the kind of Prince described by Machiavelli.
Machiavellian, although I've always thought that calling that kind of behaviour Machiavellian was like calling the creature Frankenstein.