If someone makes a political comment, they'll be rapidly downvoted by those who are emotionally (not necessarily rationally) invested in the counterargument.
You are almost certainly mistaken. Explicitly political content isn't generally downvoted because of investments in opposing positions (I do recall one possible exception, but lack of cluefulness and a bad-faith debating style were at least as much to blame there): it's downvoted because it's perceived, and correctly so, as presenting a threat to unbiased discussion.
It's well within site norms to post content with political implications, at least outside of issues relating to gender and to a lesser extent race (which are uniquely disruptive exceptions as best I can tell). People do: there's content supporting any number of possible political stances, including some seriously weird ones that don't as far as I know have actual movements attached to them. But you need a data-driven approach for this to work, and as far as possible you need to refrain from explicit political advocacy in your presentation. Rhetoric will not avail you: at best you'll get linked to the post you happen to be commenting under. More likely you'll simply be downvoted into oblivion.
People go funny in the head when talking about politics. The evolutionary reasons for this are so obvious as to be worth belaboring: In the ancestral environment, politics was a matter of life and death. And sex, and wealth, and allies, and reputation . . . When, today, you get into an argument about whether “we” ought to raise the minimum wage, you’re executing adaptations for an ancestral environment where being on the wrong side of the argument could get you killed. Being on the right side of the argument could let you kill your hated rival!
If you want to make a point about science, or rationality, then my advice is to not choose a domain from contemporary politics if you can possibly avoid it. If your point is inherently about politics, then talk about Louis XVI during the French Revolution. Politics is an important domain to which we should individually apply our rationality—but it’s a terrible domain in which to learn rationality, or discuss rationality, unless all the discussants are already rational.
Politics is an extension of war by other means. Arguments are soldiers. Once you know which side you’re on, you must support all arguments of that side, and attack all arguments that appear to favor the enemy side; otherwise it’s like stabbing your soldiers in the back—providing aid and comfort to the enemy. People who would be level-headed about evenhandedly weighing all sides of an issue in their professional life as scientists, can suddenly turn into slogan-chanting zombies when there’s a Blue or Green position on an issue.
In artificial intelligence, and particularly in the domain of nonmonotonic reasoning, there’s a standard problem: “All Quakers are pacifists. All Republicans are not pacifists. Nixon is a Quaker and a Republican. Is Nixon a pacifist?”
What on Earth was the point of choosing this as an example? To rouse the political emotions of the readers and distract them from the main question? To make Republicans feel unwelcome in courses on artificial intelligence and discourage them from entering the field?1
Why would anyone pick such a distracting example to illustrate nonmonotonic reasoning? Probably because the author just couldn’t resist getting in a good, solid dig at those hated Greens. It feels so good to get in a hearty punch, y’know, it’s like trying to resist a chocolate cookie.
As with chocolate cookies, not everything that feels pleasurable is good for you.
I’m not saying that I think we should be apolitical, or even that we should adopt Wikipedia’s ideal of the Neutral Point of View. But try to resist getting in those good, solid digs if you can possibly avoid it. If your topic legitimately relates to attempts to ban evolution in school curricula, then go ahead and talk about it—but don’t blame it explicitly on the whole Republican Party; some of your readers may be Republicans, and they may feel that the problem is a few rogues, not the entire party. As with Wikipedia’s NPOV, it doesn’t matter whether (you think) the Republican Party really is at fault. It’s just better for the spiritual growth of the community to discuss the issue without invoking color politics.
1And no, I am not a Republican. Or a Democrat.