Additionally, Larian's old implementation of Menacing Attack caused the target to run away on their turn, losing their standard action while doing so. This was incredibly unbelievably overpowered for a maneuver and could invalidate entire encounters with a single successful strike. It wasn't the same as "immediate forced movement [using the target's reaction]."
Does anyone know of an ability in BG3 that actually causes a target to *immediately* move away on the attacker's turn? If not, then I'd argue that Larian didn't implement this for Dissonant Whispers because they'd have to create an entirely new mechanic for it (which they didn't judge high enough priority).