An "ad hominem" attack is a fallacious tactic of deflection and shifting the focus of the argument. Equally so is an accusation of "ad hominem" attacks, where the accuser perceives a valid criticism as "mean-spirited" or "personal." On the surface, what the accuser's leveraging is nothing above the level of "you're just a hater" or "you're just jealous." However, what they're pretending to do is not accusing a person of being mean, but accusing their framing of the criticism as mean, as in "Your criticism is an ad hominem attack," which lends more credibility to the accusation.
What logical fallacy is this kind of deflection? On the surface, it's not targeted at a person, so it's not really an ad hominem argument. It seems to target the person's argument itself, so it's not a strawman argument either. What it only does is to mischaracterize a valid criticism and deems its tone or framing "mean," "snide," "rude," "personal," or "disrespectful," therefore worthy of dismissal.