"The scorn of the idiot is praise."
In other words, it is a waste of time to criticize the opinion of foolish people. Regardless of what you say, they will benefit from the publicity that your criticism will give them.*
If you don’t like someone’s opinion, just ignore them.
Instead of criticizing an Islamophobic website, promote an Islamic website. Instead of criticizing an Islamophobic writer or speaker, promote a Muslim one.
Instead of talking about what is wrong with the world today, talk about good Islamic manners that create a better place for everyone.
Criticizing people gives you an air of negativity. Nobody likes negativity. It is better to promote Islamic causes with a happy smile. People follow positive messages.
If you want to support Islam, make sure you do it through positive messages, not negative ones.
* It can also mean: When a foolish person expresses anger at you, consider it praise. When I first read the quote this interpretation didn’t come to my mind, though now it seems to be the more intuitive one.