That was my point, it's not about curtailing aggression, it's about channeling aggression.
Castellanos shouldn't even think about swinging at a breaking ball until two strikes, he's not going to hit that low and away breaking ball even if it's a strike. Same with a FB at eye level, how often does a hitter every make good contact on those.
The whole idea is you attack pitches in your sweet zone, where you have the highest probability of success, and lay off everything outside of that zone until you have two strikes - at which point you choke up a little and focus on contact.
The other thing is if you haven't seen a pitcher before, it's usually a good strategy to watch a few pitches and get a feel for his stuff instead of swinging blindly.