I have already had moments where I've crushed his spirit. I've seen it. He cried and told his grandparents "I'm sad because I'm a naughty boy and I want to be good" and he was really subdued. He also says, "Don't scold me, Mama." and I have had to apologize to him for my harshness. But it doesn't change his willingness to listen. It does change my willingness to keep correcting his behavior. Because after all, he's only 2.
The thing about spirits is that they are remarkably resilient, so it's okay for him to get down once in a while. This is also where it's important to intervene so he understands the message is about the behaviors and choices, which is something he can control, rather than a permanent judgement on him, which he can't. "You're not a naughty boy, you just made a bad choice. Next time, you can choose differently."
It also looks like you're effectively handing him the tools to manipulate you. If he commands you to stop scolding, and you respond by apologizing, you've allowed him to take control of the conversation and steer it to his own ends. If he's making you reevaluate your commitment to correcting him, then you're allowing him to sabotage your best weapon, which is consistency.
For commitment, it helps to keep in mind that any behaviors you're trying to correct are for his benefit, because they'll either keep him safe, or help him in future social settings where you're not there to guide him. In either case, he's far better off for you to correct him than if you don't. Two is the best time to be teaching these things, rather than years down the line when they've become ingrained habits.
My DD9 still says, "Stop yelling at me," when we're disciplining her in a normal tone, because that's an uncomfortable conversation for her, so she responds with a normal avoidance technique.
