I don’t know how someone makes something such as this. Video montages are extremely grueling work. Bear in mind that for each sliver of video footage used, an entire clip needs to be sought, found, and downloaded.
For example, the latest Metaflix video, “Cinema of the 70s – Starring New York City” features clips from a dozen or so movies. The video itself is under 7 minutes in length and about 500 megabytes. The source material, however, comprises 150 different files amounting to well over a gigabyte of storage.
Seeking out individual words or phrases from 183 different movies is simply beyond my comprehension. There must be an automated tool or extension of some sort that does this. Otherwise, The Unusual Suspect, who made the video, and everyone else of his or her ilk must be a little sick in the head.