I disagree. Mobbing existed before anonymity; in fact, it was very much the norm -- the concept of "honor" is often tied to public displays of condemnation for the "dishonorable". Publicity makes it harder for people to disagree with what is perceived as the opinion of the majority, as unpalatable and uncivilized as it might be. This is why political votes are secret, among others; or why the Gospels explicitly warn against public displays of faith.
Every group of people will have its "dishonorable" enemies, and will always be keen to publicly shame them. Forcing people to attach their public identities to online activity will do nothing to dissuade people who see such actions as a badge of honor, but it will chill the display of dissent from the status quo.
Mobs existed before because there were so many people that you were effectively an anonymous member of it. Similar to behaviour in protests today.
However removing anonymity today would be difference since everyone could see your name and could get you fired, killed etc. Hence the OP is right that you would see less mobs.
Removing anonymity will just reduce the possibility to express a dissenting opinion. This is why authoritarian systems the world over have always loved ID cards and the likes.
Even the event you mention probably depended on many being able to participate without risk, since one guy alone doesn't make for a very convincing 'mob'.
There are arguments for anonymity online, and I tend to agree that they outweigh the problems. I think it'd be strategically better to focus on these than try to attack the rather intuitive logic at the core of such calls for ending anonymity.