Virtue signaling involves intent, so a person pointing out something is, say, misogynistic might do it because they are really concerned about the topic and it's the way they feel, even taking the risk of an unpopular opinion. Whereas someone denouncing them for virtue signaling is overtly engaging in virtue signaling, i.e. publicly proclaiming their distaste or disinterest to the topic.

Unlike the first case, there is no larger public interest the denouncer claims to protect.

Nope, I absolutely do not, nobody in my life has ever accused me of virtue signalling or even implied it. Try again.