That etymology for 'Britain' doesn't seem to be referenced anywhere else—the link in the post you've linked to hasn't worked since 2003 and doesn't cite its source either. Seems the name derives from Brythonic (British Celtic) and meant "the painted ones" or "the tattooed folk" rather than a reference to tin. The etymological path it took was (roughly): Brythonic -> Ancient Greek (by way of the Greek explorer Pytheas) -> Latin -> Old English/Middle English/Old French -> Modern English [0][1]
According to the Senate report on the matter[0], Backpage would systematically help posters reword illegal ads to appear less so:
"Backpage has publicly touted its process for screening adult advertisements as an industry-leading effort to protect against criminal abuse, including sex trafficking. A closer review of that “moderation” process reveals, however, that Backpage has maintained a practice of altering ads before publication by deleting words, phrases, and images indicative of an illegal transaction."
Scanned the executive summary. That does sound like they aren't good guys. As I posted above, putting down backpage as a whole puts a lot of sex workers at risk, but this gives me mixed feelings about backpage in general.
Yeah—not arguing the overall wisdom of law enforcement's approach here, but it's important to understand how much these guys were aware of the illegal activity on their platform and chose to actively facilitate it.
It's not an ad hominem. "You're not an anthropologist, so what you said is wrong" would have been an ad hominem. The GP actually attacks the argument, although somewhat incompletely (to be polite).
EDIT: The authority is actually named, it's "anthropology".
1. No. There was no personal attack, and no fallacious reasoning from any personal attack. 2) An intellectual field is a very abstract form of authority, in this context.
1. Saying someone said something is a personal attack? Let me rephrase: "The textual information that became visible to me once the reply button was pressed on your computer" — or is my use of 'your' still out-of-bounds?
2. I didn't include enough detail in my post to actually conclude whether my appeal to authority is fallacious, since that entirely depends on in what manner I'm citing the authority. On the other hand, the post I responded to contained implicit appeals to supposed authoritative information ("There is a universal correlation...", emphasis mine) and the subsequent conclusions based on that authority.
I thought it was pretty self-evident that torpedoed your entire comment by claiming 'universal correlation' across all cultures and organizations—was any further response to that really necessary? You're throwing around gigantic assumptions that don't bear up under even the most minor investigation into the nature of power and respect cross-culturally.