I do not know about this specific case (looking at the subreddits I truly doubt it is an example) but there are examples of systems using anti-harrassment as a means to censor particular groups, links, and ideas.

With a title like "'Troll hunting' algorithm could make web a better place" (http://www.wired.co.uk/news/archive/2015-04/14/google-algori...) this algorithm seems like a true boon. It's only slightly suspicious (and can easily be explained away) that two of the three websites used in its study were political websites. You'd have to be pretty zany to leap to the conclusion that the paper had anything to do with censorship.

It would look worse if one of its co-authors (Cristian Danescu-Niculescu-Mizil) received funding from the DoD to study the propagation of information through social media online (http://arxiv.org/pdf/1504.01383.pdf) as part of DARPA SMISC - a strategic communications (DoD term for propaganda) research group that studies how information flows on social media and how to direct and disrupt it.

Many researchers take grants from all over though, and anything in this area of study is likely to get investment from the DoD. So still it's more reasonable to think that, since he works in that area, of course he will receive DoD funding.

Yet it was posted with 22 likes to NATO's Strategic Communications Centre of Excellence (https://www.facebook.com/StratComCOE), a Facebook wall also contains a review of a book called "The Weaponization of Social Media" and announces its participation in a conference on “Cyberattacks and Propaganda: the Battlefield of Future”.

As evidenced (again) as recently as this week by a group of people who run an anti-TPP website, there is an inter-website system for blocking posts to certain content (https://www.reddit.com/r/technology/comments/38pmg8/hey_redd...) - Youtube, Twitter, Facebook, etc all simultaneously blocked this website. Whether this was an error or not (it probably was), it points out there is a centralized system for blocking content.

Both the Facebook emotion experiment and the Facebook vote experiment had ties to funding to the DoD (and Air Force though blurbs about funding from the Air Force, which handles cyber in the US, was erased from the academic's page when there was public attention; it was reported to be a clerical error).

This is not to say that this is used inside the US to block US contibuted content. While the history of the United States Government in applying strategic communication and information support to US audiences has been slippery, and the Smith-Mundt Act (anti-propaganda law) was recently weakened under the justification that global interconnectedness of conversation, news and social media makes it difficult to prevent US propaganda intended for foreign audiences from making it back home.

The new CEO of Reddit is on the board of a Washington Defense Thinktank. This anecdote doesn't imply anything. But it does mean that you should be asking Reddit and its CEO hard questions, you should be skeptical of intentions, and you should demand that Reddit - like all other companies that own your communications and socialization - keep themselves to the highest possible standards.