If you're on about the TO escanor vs Assault mode meliodas, uhhh Escanor resisted it against Melascula, and in doing so did a shit ton of damage to her. Also that's not the point Speedster's trying to make. He said Meliodas will keep attacking, untill its useless and will then soulmanip due to his emo nature.
Assault meliodas didn't do this, because TO would never give him the chance to do this, and because he already resists soul manip. And also because TO was kinda hard bodying him the entire match.
I see no reason why AM Meli would not soul manip if everything else proves ineffective, and the argument of "but Escanor" makes 0 sense. Like why pick the one character whose actively shown to resist soul manip, as proof AM wouldn't use it.