If Dave overlooked this incident, future transgressions would likely escalate, with others following suit. He didn't need to wait for further provocations to take decisive action.
The worst part was that if such behavior escalated into malicious actions, it could endanger someone's life—perhaps not Hera's, but anyone the maid perceived as competition or a hindrance.
Dave was acutely aware of this risk, which is why he knew he had to address the issue promptly before it could spiral out of control.
Dave had seen countless wealthy men keep mistresses, and more often than not, those mistresses started as maids working for the family.
If he allowed the situation to continue unchecked, the maids might start believing they had a chance with him simply because he let them mistreat his woman.
This would only fuel their misguided hopes and deepen their delusions about him.