Monica was at least 19 years old when this Clinton thing got started. She looked and acted like what she was: a full grown woman who knew what she was doing. So this was not abuse. Clinton did abuse and forever taint his position of office though.
At the time the Left was pushing, hard, a variation of sexual abuse based on power differential.
Sexual activity, by their standards, could not be consensual if there was a power differential between those engaging in sexual activity. Basically a low-level female employee, even if an adult, really couldn’t consent to sexual activity with a superior or someone more powerful than she. By this definition the sexual activity was assault and/or rape.
Then the President of the United States got caught engaging in sexual activity with an intern. All the “power differential” talk stopped. Immediately.