Why did Mark Zuckerberg tap the front camera of his laptop?

As a computer expert he know that we can hack computers Cam. So to escape from this he choose this way. By the way the permissions which we are giving for various apps to obtain control over microphone and front Cam in mobile phone will make u more vulnerable to attacks. They are legally using all our personal information for various reasons like making the apps more attractive and to recognize what we really want. For example they can watch our facial expressions while watching videos and suggest the similar kind of things to u. So u spend more time on it and that's what exactly they want.