Is Central Bank Forward Guidance an Institutional Trap or a True Roadmap?

Why does the market dump an asset immediately after a central bank announces an interest rate cut that retail traders were eagerly expecting? Central bank forward guidance and policy rate decisions are priced in by institutional swap markets weeks or months before the official press conference occurs. When the actual rate cut happens, institutional capital uses the influx of retail buy orders as liquidity to close out their long positions, triggering a buy the rumor, sell the news crash. Is following central bank forward guidance actually a lagging indicator for retail execution?