This is terrible advice. Most if the time bullies are looking for a reaction. If you give it to them they will keep coming back for more and escalating further and further if you try to ignore it.

What bullies are looking for is fear, embarrassment, shame, impotent rage, and the like. If you give it to them in any form they will never stop.

If you're capable of fighting them and winning, sure, that's a solution. If you're half their size and they can easily destroy you any attempt to fight back is just going to make them laugh and beat you up every day.

The first trick is to never rise to their bait. The second is to show confidence and lack of fear. If you project the idea that you don't want to fight but you're not going to back down from one, either, they will not target you and will usually pick on someone else.