In the free marketplace of ideas, Reddit is the pure, unregulated street bazaar of American thought.

But that's changing a little, locally, with the announcement late last week that the r/Minnesota sub-reddit page would begin to more heavily police racist and offensive comments. As explained by a page moderator, posts that cite race or ethnicity as the cause of a person's behavior will be removed; repeat offenders could get banned from the site altogether.

The rule change follows some tense months of heady local topics that have inflamed language and feelings about race: Jamar Clark's death; the shooting at the Fourth Police Precinct protest site ; Black Lives Matter disruptions at the Mall of America and the airport; and St. Paul cop Jeff Rothecker's previously held position that those protesters should be run over for blocking the street.

Resulting conversations on the Minnesota-focused Reddit page have brought in the racists — or maybe brought out the racist in some people. These comments, the moderator writes, "sink way below the level of discourse we would like to see," and are making "people on different sides of complex issues get even angrier with each other."

Some moderators who run the page are in disagreement. Aside from it flying in the face of free speech, the policy change raises the question of whether other categories, like religion, gender, or sexuality, need the same protections. "We recognize that this rule will most likely be controversial." They guessed right.

Black Lives Matter "brings out the worst" in some people. Racists, mostly.

The announcement has drawn hundreds of responses, with many users questioning the need to actually take down comments from a site that's known to allow all sorts of perfectly offensive material. Writes one: "I think it's a terrible mistake to start having a select few pick and choose what gets allowed and what doesnt [sic]."

The whole chain of responses is worth a read, if only to see how an unwieldy mob tries to navigate the bounds of allowable communication. One guy immediately tests the moderator with a joke, which elicits the reply, "You're stupid but that's not racist."

Want racism, say others? Check the comment section of any story published on WCCO or the Star Tribune.

The announcement followed closely on the heels of our story about anti-Somali racism in St. Cloud, so naturally one branch of the Reddit conversation devolves into jokes about — or strong defenses of — that city, thus leading to a fight over whether being prejudiced against people from St. Cloud makes you a racist. (Is "St. Cloudian" a race?)

Other users suggest some of the racist talk is coming from users who were sent as plants from other, explicitly racist corners of the Reddit world, to deliberately interject white supremacist chatter as a way of recruiting new members to their cause. This theory of the outside agitator come to spoil Minnesota's good-natured debate is in line with the most popular, most up-voted response to the rule announcement: Trolls or true racists, those kinds of comments are "un-Minnesotan and un-American," the user writes.

It's a nice thought. But it's only true if every single instance that's troubled the r/Minnesota moderators was actually the work of people who don't live here. Racism is, in fact, rather American, and at least a little Minnesotan.