There are multiple readings of "Assume Good Faith". I think pi zero was pointing out that it can be used to justify 'violent' communications. "Oh, sure, it might seem like I just punched you in the nose, but you must AGF and respond as I were just trying to kill a mosquito that happened to have landed there." David Gerard's "stupidity" reading of AGF would be, "...respond as if you just clumsily knocked into my nose, since clumsiness is more common than malice". Both variants of the assumption can be abused by malicious actors.
The problem in all societies is how to establish mutual trust; part of which requires protecting the society from malicious actors. AGF is only one part; it works to soothe "common clumsiness" while malicious actors need to be dealt with via other means. We shouldn't really evaluate it in isolation from the other mechanisms in our society
It's certainly an interesting point that AGF excuses incivil conversation and puts the burden on the listener to compensate, which is a rather Torvalds-ian approach. But the linux-kernel mailing list seems to be WP:AGF without WP:CIVIL. WP:CIVIL puts the burden on the speaker. Balance! --scott