That statement applies more to heavier aircraft than RJ's. A go around verses a TCAS RA are somewhat different animals. The TCAS system is built around certain performance expectations that might not be available at Vapp dirty in some or most aircraft. Somehow TCAS would need specific weight and other performance data before commanding a avoidance climb rate. The current TCAS system is geared to aircraft operating with a substantial performance margin. It's basically generic. That margin is not there at Vapp.