because he's on Sky Atlantic, a subscription channel. We can say it has a viewership of under 700,000, because that's what you need to get into the weekly top 30 for 'Other' channels in the publicly available viewing figures: http://www.barb.co.uk/viewing-data/weekly-top-30/ . I suspect it's well below that - More4, a free-to-air channel, couldn't keep enough viewer interest in 'The Daily Show' to keep it going.
"In fact, many believe the airing of Oliver's program on Thursday night, after the Brexit vote, is what led Brits to "frantically Google" the EU after the vote was over."
Only people who have no idea what people in Britain watch would think that. I suspect that means the person who wrote the paragraph, and the first person they talked to, in the office or on social media. The idea that people who watch a niche show that aims at people with an interest in politics, hidden on a subscription channel, would be the ones who are googling simple questions on the EU is pretty dumb.