Movement is often just another word for exercise. Movement just feels like a more precise word as e.g. the bench press "exercise" can be done in different movements. Just compare how a powerlifter bench press vs a bodybuilder.

You may have done an exercise for a long time, but small changes to your technique/movement can have a big impact.

It's also more descriptive. When I said they look new to the movement, it is based on how they move the bar. It doesn't look "refined" and their nervous system hasn't yet nailed down the movement pattern. That could be because they've never bench pressed before, or it could be because they are trying a new technique.