Hardcore porn is embedded all over regular-ass websites because a porn company has purchased the domain of a popular, defunct video hosting site.
As pointed out by Twitter user @dox_gay, hardcore porn is now embedded on the pages of the Huffington Post, New York magazine, The Washington Post, and a host of other websites. This is because a porn site called 5 Star Porn HD bought the domain for Vidme, a brief YouTube competitor founded in 2014 and shuttered in 2017. Its Twitter account is still up, but the domain lapsed.