Listen, praising God's name is the same no matter which way you do it. It's the same exact words, meaning, just different to the ear.
Does it say anywhere in the Bible that God would not like us to scream and play loud music when we worship him? Didn't think so.
Metal has become a sterotype. That's hard to change once it's set in someone's mind, but for the openminded, realize its only what our ears sense that is different.