This may have happened both before and after the Napoleonics, but this is when I know. Also, I know there were plenty of cases where artillery was used to break up infantry formations, but from reading, it seems as if the broad/default strategy was to respond to enemy artillery fire. Why?
Before the French Revolution, artillery useable was very poor since most commanders didn't believe it warranted any importance but during and after the Revolution it was very useful to support untrained infantry or in Napoleons case, help drive the iniative to attack.
However, if artillery is deadly, so is the enemies. Just as /u/DragonflyRider mentions, counter battery fire is useful in protecting your own infantry. However it's a case by case basis since Napoleon use his artillery to help his offensive abilities by attacking points his infantry was attacking, which is the true skill of Napolon as a commander.
It was not always used thus. But if you can knock out your enemies artillery, he can't respond to your dominance of particular places on the battlefield. If I can kill all your arty, and you can no longer mass its fire at one of my columns, I can go where I want without fear. Plus I can mass my fire at one of your columns, and keep you from taking advantage of a superior position without cost.