In many ways I admire the effort some of the posters put in to rationale take apart some of the arguments put forward but I also sit there thinking, why bother this person is just plain thick and will dismiss anything you say and carry on regardless.
That may be so, but I keep in mind there are others who are reading also, lurkers who may appreciate a rebuttal and not just "that guy's so stupid." Random drop-ins who search terms on google find and revive very old blog threads and sometimes forum threads might find an answer more helpful. I can't know this to be true, but I think also fundamentalist doody-heads like to troll and see the atheist lose his shit, they think they've won the argument. While I borderline lose my shit sometimes, I still try to argue against what they are actually saying, for the variety of reasons that a) lurkers may actually be looking for info and find out we're not just about losing our shit, and b) writing out the answer for myself. I find this blog helpful for me sorting out my own ideas, how I feel and where that came from in me, make sure I think what I think, be myself, and not just conform to a stereotype I feel comfortable with, joining, socializing to the group. And also c) which is more relevant to this next part:
As for the "agressive" atheist ... I can't help but feel this is just another term, along with fundamentalist atheist, that's banded about to try and discredit what is being said without addressing what is being said (this may seem somewhat hypocritical compared to what I've said above but I have no intention of repeating the same objections that have been raised to stupid argument again and again and again). It would seem that the term is applied to anyone who doesn't show the required respect to religious views how every ridiculous they are.
As you described your tone in real life is much more subtle, I have trouble with that. I tend to get more easily flustered in a face-to-face discussion (about anything) and come off weak and shy or combative. If I know what I'm talking about, it probably sounds more douchey to people who don't want to hear it than I really intend, and if I don't know what I want to say, I might go straight to losing my shit, or I might clam up to avoid losing my shit and say nothing. I'm not that good with direct questions and answers face-to-face, so maybe I like writing it out better as I have time to think, but also maybe to work out having the words I need. Editing and getting to the point have always been a problem for me, believe me, I'm working on it and have improved in the last decade I've been on the internet, but it's another reason the face-to-face is hard for me. There are people on here I wish I could punch, if you want to know how I really feel, but well, that wouldn't be a good image either. I do think people are too sensitive to having their beliefs challenged no matter what you say, but I also think it's important to have numbers of us, atheists, and let them think what they think until they notice that we are beside them at work and on the train, their neighbor... somehow. Without saying much of anything, how a lot of us challenge their beliefs saying nothing to them, and they get defensive for no reason and accuse us of being aggressive. Little/big things like challenging the manger scene on the town hall lot. They might not like it, but they have to live with it, and they know we're in their town. It's just a set of props, it's not actually Jesus, you know! I mean, threaten them with billboards and poster campaigns, they always vandalize them, but we're there. They're the ones losing their shit.