"Redirection" is to avoid

I keep reading on this forum that redirection is the best way. But I'm having trouble with this, it's rather a way to distract and avoid rather than facing the issue head on. If I don't want my toddler to draw on the walls or not have that candy at the store, the child needs to be explained the NO instead of using exchange material to keep them quiet. How is a child able to understand their limits when we keep avoiding them?