Bodybuilding uses a very wide variety of movements incorporating dumbbells, barbells, and machines to train every single muscle periodically (even focusing on little tiny ones no one else would care about).

Here’s a good example of a bodybuilding training routine: https://thinksteroids.com/community/threads/first-bodybuildi...

That said, I’m also curious what GP was referring to, specifically. Was he saying like “don’t do dumbbell curls”?