Haha, some of them are hilarious. Some more obviously generated than others, but still... good job.
How are they generated?
I managed to get some gems like this:
> The earliest Nordic settlers in the Old Northwest were shocked when they discovered their lands had been inhabited by a sentient race, which has been confirmed by scientists to have used Google products over 300 years before today.
I'm guessing Markov Chains[1]. Effectively, each phrase is determined randomly from a pool, the options are dictated by the preceding sentence. They're a surprisingly effective way to produce a few sentences that seem logically connected, despite being more or less random. After a few hops, of course it can go off the rails.
And they have a simple grammar that allows them to pull famous names, places and drop them into predefined slots. Someone else already pointed out, it's basically Mad Libs.
It looks like the theories were pre-generated, then on refresh, the front page just shows a random theory..... or at least that's what the author wants you to think... until it's too late. Numerous pop-songs from the 90s make reference to this.
In all seriousness, I'd love to see the source code.
How are they generated?
I managed to get some gems like this:
> The earliest Nordic settlers in the Old Northwest were shocked when they discovered their lands had been inhabited by a sentient race, which has been confirmed by scientists to have used Google products over 300 years before today.