>While this a completely logical course, my argument is that the practice of constantly trying to subdue such feelings, in my experience, is in itself harmful.

It's not about "subduing" or "controlling" emotion. It's about accepting them. In other words, you don't stop your feelings - you let them run their course. BUT you grow your awareness of them so that your feelings don't immediately result in bad choices and harmful behavior. That's what stoics meant when they talk about the passions ruling you. It's not that the passions themselves (the feeling of them) rules you, it's that you let them dictate your behavior.

Instead of reacting to your feeling of anger by physically attacking something or someone, you pause and say to yourself "wow, I'm truly angry" and focus on processing that emotion. You acknowledge and analyze your feelings. The more you practice this, the more you're capable of riding the emotional roller coaster of life without jumping off or being paralyzed by fear.