arrogance to claim that you know someone's opinion better than they do
You're lying. I did no such thing. I am not saying you don't know your opinion, I am saying you are knowingly and intentionally lying about what your opinion is.
You know that I gave you a reasonable response
That response was not reasonable.
You're a liar.
tidal wave of half-truths, and occasionally peppered in utter bullshit
You're a liar. The fact that you cannot address, let alone rebut, my arguments doesn't make them false.
You then closed with
You're a liar. There was not a single insult in there.
You are also wrong that I offered any arrogance, but you could actually believe that. But you cannot believe I insulted you, unless you think "you're lying" -- a true statement, since I said it in regard to the false claim that we "rolled back every regulation we possibly could" under Bush (which I charitably interpreted as a reduction in regulation) was either the result of intentional dishonesty, or reckless disregard for truth or falsity, and either way I hold you responsible for the claim sufficient to justify a claim of lying -- is an insult. But even if you want to claim that as an insult, that would be the only one. Nothing else even refers to you except to identify you as the person I am talking to.
and that you responded with pure ad hominem back, whining about a disagreement over what began as your ad hominem directed at me.
That was not an ad hominem attack
I didn't say it was. I said it was pure ad hominem. Whether it was an "attack" is uninteresting: the point is that you responded to my comment, which was all about the topic of discussion, and instead talked about me, personally. That is the definition of "ad hominem."
You hadn't written a single comment here on slashdot in over three months
You probably don't know this (if you do, you would be lying), but the comment history doesn't actually show all the comments you've posted on your account. Take a guess what comments aren't shown!
You then chose to take it personally when I pointed out that you were gone for three months.
You're a liar. I made no such choice: it literally and explicitly was personal. It was nothing but personal. It was all about me, and not at all about the discussion.
You certainly haven't demonstrated any reason to expect that you are here to have an actual discussion.
You're a liar. I just provided the evidence: I posted a reasonable reply to your arguments. You then replied with pure ad hominem.