this post links to the wikipedia article "stream capture" (which the article says is also called stream piracy).

the article is about fluvial geomorphology.

the title i chose for it ("Stream capture, also known as stream piracy, is not a good alternative to bittorrent") is a joke, premised on the fact that the terms "stream capture" and "stream piracy" can also refer to ripping (aka capture, a technique which can be used for piracy) of streaming media.

BitTorrent is a popular protocol often used for pirating media. In truth, capturing (video) streams is an alternative to using BitTorrent for piracy, but the quality of media one can find on BitTorrent is often much higher than what one can find on streaming sites. So, many discerning pirates would agree with the statement in the post title. However (in my opinion, at least) the incongruous subject of the linked article makes this funny.

See https://en.wikipedia.org/wiki/Theories_of_humor#Incongruity_theory for more information.