If B were truly anonymous, then A would not be able to Bully him. Go ahead, try bullying an anonymous coward on slashdot. The idea doesn't even make sense.
Ability to remain anonymous legally in a jurisdiction does not mean everyone is completely anonymous. Ability to carry a loaded gun does not mean everyone carries and is trained to use one. Anonymity in the bullying case is so similar to guns, even fallacies are alike !!
The outbreak of Facebook has ensured 99% of internet users are "effectively de-anonymized". An outbreak of a similar disease in the gun world would ensure guns are rendered useless as a defence too, by de-gunning 99% people.
So what? His pseudo identity will be booted / ip banned, his comments deleted etc.
1. No, online platforms today have done a horrible job in protecting most cases of bullying. There is no reason why de-anonymization laws in one country will suddenly make all online platforms completely cooperative with that one country's vicims in relieving them of the bullying. It is a huge uphill battle to even convince Facebook that a registered account is bullying. Many of those online platforms are not based in that country.
Even if they did get so cooperative suddenly, the bully can change identities and bully again.
"Polite society" can trivially banish and ignore the 'anon' person, and there's nothing he can do about it.
If there were a polite society, online bullying wouldn't be allowed to go so out of control, even without anonymity.
Nothing like guns. ... The guy with the gun can't simply be tossed out ... because he has a gun.
The childish argument of gun superiority. A person you don't know, don't see, attacks from any direction, and cannot be attacked back s infinitely more terrifying than a steel nerved, gun wielding, shooting champion enemy who is de-anonymized.