Yes they are two different things, we agree. The players should be professional and immune to it, we agree. And, if you would have done the same thing Artest did, then you would have an early off-season.
Just like Ben Wallace says, "I don't feel sorry for him, you have to take responsibility for your actions."
Your other argument is misleading. You have to understand, if you throw a drink on me, and I punch you - it's different than if you throw a drink on a professional and he attacks you. Professional athletes are held to a higher standard than "everyday people." So, while Charles Barkley is making a point, it's not a good one.