Before Reddit started worrying about advertiser friendliness and cleaned up its act, there was a thriving network of hate subreddits. Probably a lot of overlap with the /pol/ population, based on the amount of overt, disgusting racism to be found there.
Anyway, I wrote some crappy Python that would go visit my carefully curated list of racist cesspool subreddits, hoover up all the post and comment text, and add it to the corpus, then some more crappy Python that would ingest the corpus and do Markov chain stuff to spit out some fairly convincing internet hate speech. I think the key to my success was that frothing racists in comment threads typically aren't putting forward the most cogent arguments anyway, so it's a pretty low bar.
I didn't post this little project or write it up anywhere, because I felt bad enough having brought it into the world, but it was good for a chuckle, at least for a little while.