I believe his history as a snake oil salesman is highly relevant to his current "security" work.
Doesn't mean it's not worth talking about, though. After all, science is entirely founded on a kind of inductive reasoning, so logical fallacies aren't crazy to consider.
Gibson's personality isn't the thing in question here, the quotation above is specifically about his history in security. If the comment was about how he's a major asshole (just an example, I'm not saying that) in conferences or something like that, it would be an ad hominem, as that sort of information would not be relevant.
His history as a security professional has no bearing on the actual content here. We are all talking about an idea SQRL not Steve Gibson. If you said, "SQRL isn't worth my time because I don't trust Steve Gibson" that's fine, but the author made no note on SQRL at all, he just attacked Steve Gibson and let it be.
Sure there may be precedence to say that SQRL isn't worth your time, but Steve's credentials don't affect this idea at all. For all you know he may have been given the idea by a team of security researchers who wanted to see if the top post on Hacker News would be some bull shit argument about Steve Gibson. Obviously not the case, but come on let's talk about the freaking content here not the man.
The saying "throwing the baby out with the bath water" comes to mind. Let's look at SQRL and see if it actually makes any sense before we throw it all away.
- Examples of Gibson's previous ideas that have been proven fake
- Examples of Gibson's previous projects that have security flaws
- Examples of projects that Gibson is purported to "peddle" through his "snake oil salesmanship"
- A quotable, referrable, expert opinion of Gibson's standing, or lack thereof, in the broader security community
The post includes none of those things. It is no better than saying "$NAME is a bad person!"; it merely uses more words to say so.
note that i am not affiliated with grc; my name is permuted :)
So yes, regardless of what your link says, the argument is an ad hominem.
Bringing the quality of a person's previous work into the discussion is a necessary shortcut. We can't all be expected to have expert-level knowledge on everything.
Sources:
http://plover.net/~bonds/adhominem.html
I think this example is pretty much what you did.
A: "All rodents are mammals, but a weasel isn't a rodent, so it can't be a mammal."
B: "I'm sorry, but I'd prefer to trust the opinion of a trained zoologist on this one."
B's argument is ad hominem: he is attempting to counter A not by addressing his argument, but by casting doubt on A's credentials. Note that B is polite and not at all insulting.If you want further reading from other sources you can go to any of the following links. en.wikipedia.org/wiki/Ad_hominem http://www.nizkor.org/features/fallacies/ad-hominem.html http://c2.com/cgi/wiki?AdHominem
Also, you've presented no actual rebuttal of whether Gibson's history is relevant to evaluating his present claims. Rather you've merely stated the name of a logical fallacy. Which is, itself...