What if ....
A poster, who goes by his real name, says that another poster,who uses an alias, is a danger to air safety or a dick head or something similarly defammatory?
I guess he can't be charged ... as no real person was defammed.
It therefore follows that the only real protection against someone telling porkies about you, or belittling you is to go by your real name.
It further follows that there's probably only one or two people on this forum who have protection against defamation, and they can say what they like about the rest of us.
OR, we could all go by our real names ... and sit politely at the computer desk, too scared to say anything.