Another apologist with his "clever" questions

[Jesster]

Not that I necessarily want to place Dawkins on a pedestal, but calling someone a big bully is not an ad hominem. An ad hominem would be "you are a big bully and therefore your opinion is wrong".

An ad hominem is a fallacy because you're not attacking someone's ideas. You're attacking them.

Insulting someone isn't necessarily doing that. You can insult someone as a conclusion of your argument against them without using that fallacy ("you are wrong, and therefore you are a big bully"). If you use the insult as a method of attacking their ideas, then yes, it is an ad hominem.

I'm not entirely sure if Dawkins has made that fallacy or not, but the way you worded it didn't make it sound that way.