Okay, so I went back as far as could (easily) go into my own posting history -- 1000 posts, or about 1/8th of my total. While I will admit I didn't read each post in detail, I'm pretty sure I did what you did, which was to read the first few lines of each one as provided in the search results. It was rather educational, I've never done anything quite like that before.
The interesting thing is that I actually tu quoque fairly rarely. My normal pattern is to pick a couple of threads at a time, maybe as many as 4 or 5 in a sitting, and get into some long drawn-out argument that has nothing to do with either right- or left-leaning politics -- whether a portion the Constitution can ever be unConstitutional, Texas authorities confiscating tampons but allowing guns into the capital building, that sort of thing. The drawn-out nature of the argument is usually my fault, as I often fasten onto a point and worry it like a dog with a bone.
At any rate, I'd estimate that I engaged in tu quoque towards the OP of troll threads like this one well under a dozen times in my last 1,000 posts. Normally when I talk about bad behavior or government reform, I talk about it without referring to a party at all, like when I talk about overcriminalization or hysteria in politics. I do from time to time run into people who interject a criticism of one party or the other in an off-topic manner, at which point my message is generally that both parties suck, and if I elucidate upon a solution it is to abolish the 2-party system and make room for more political competition.
Does that other flavor count? Seriously, I'm not sure and I'm asking your opinion -- because in that case it's something I stumble over randomly in a thread and I generally respond with both sides suck and need to go away, versus going to a thread specifically to remind the OP that their specific side sucks too.
In the end, I think you're probably right -- when I step into a troll thread specifically to counter someone's pointing and laughing at "the other side," I do it more often to right-leaning posters, but I do it so rarely to begin with. I guess I locked one particular counter-example in my mind (when I stepped into yet another Tea Party racism thread to insist that a few nutjobs don't represent the Movement in any way) and that sort of eclipsed anything else.
