You needn't look far—there was a personal attack in your GP comment: "you sound, frankly, like some sort of political zealot". Swipes like that are certainly not respectful, and they're definitely not ok in HN comments. Actually, every single sentence in that comment had some sort of swipe in it.
If you don't think that was crossing into personal attack and breaking the site guidelines, you're underestimating the impact of your comments. it would be a good idea to recalibrate by reviewing https://news.ycombinator.com/newsguidelines.html and remembering that this sort of comment always lands with far stronger impact on the reader than the commenter thinks it will. Objects in the mirror are much closer than they appear.
"you sound, frankly" -addressing their extreme rhetoric, not them. How they come across is different than who they are. Every statement was a "swipe" at their disrespectful and unreasonable arguments, not them as a person. If I'm not allowed to defend my ideas and position, respectfully, in the context of discussion, within site guidelines, what's the purpose of discussion? It's enough that respectful, in-context posts I've made on controversial topics have been flagged and removed regularly here. Is this supposed to be another reddit/4chan echo chamber?
> addressing their extreme rhetoric, not them. How they come across is different than who they are. Every statement was a "swipe" at their disrespectful and unreasonable arguments, not them as a person.
That's not how internet comments work. If you tell someone they sound like a zealot, you're calling names. If you then say "I didn't mean it about you, only about how you sound", that's a distinction that makes no difference to the receiver, with whom your comment has already landed like a punch.
I'm afraid the problem is that your comments aren't as respectful as you think they are. This is a common problem, as I tried to explain above. Swipes that feel harmless or perfectly kosher to the commenter can easily land with readers, and especially with whomever they're replying to, as aggressive.
Because of this asymmetry, it's easy to end up with a flamewar in which all parties feel aggrieved, like they're the innocent one who did nothing, while the other is the one who behaved badly and escalated. Everyone ends up feeling like they're just defending themselves from unprovoked attack. In reality we're all subject to this cognitive bias, and if we're to avoid having this place go into a downward spiral and burn itself to a crisp, we all need to be extra careful to err on the side of being respectful and editing swipes out of our posts here.