But, yes, it's also true that everything is calculated to appeal to (primarily) DCMediacrone. Genuinely hating GG and leveraging DCMediacrone's hatred of GG to his own ends definitely aren't mutually exclusive.
He's stirring up all the usual hornets in her brainpan and doing his best to substantiate all her obsessions and suspicions. Negz has no higher scruples beyond his own personal gratification and he's fundamentally amoral and self-seeking; the only thing subhumans like Negz understand is manipulation with the aim of fulfilling their idiosyncratic desires.