In reality, ordinary people were talking about it all the time. It was just that academic books were not being written, and government officials and other people in power weren't talking about it. Cecil Woodham-Smith published The Great Hunger: Ireland 1845–1849, which became a bestseller and was even serialized in newspapers. Folklore researchers around that time discovered that stories of the famine were very common in Irish folklore, and even songs had been written about it. The Fields of Athenry is a famous song about the famine that is still popular today and is sung at soccer matches, similar to the way we play the national anthem.
The historian in the video made a good point that there are still villages and isolated huts all over Ireland that were abandoned during the famine, and it would be very hard to ignore these very obvious signs of it. My own opinion, which he didn't mention but makes sense to me, is that newer generations would naturally want to know why they have family in America, Canada, Australia, or elsewhere. That question would be impossible to answer without mentioning the famine if that was the reason their ancestors emigrated, as so many did.
So, in reality, it was just that official and academic books weren't being written. There was a huge revisionist movement at the time, where people were reluctant to write anything that was overly critical of the British government. According to the historian Mary Daly, she was reluctant to write about the famine because she didn't want to produce a work that might, in some way, support the IRA, and she believed other historians felt the same.
Ironically, some of the next books to become popular with the public were written by English historians, including Cecil Woodham-Smith's The Great Hunger: Ireland 1845–1849 and Terry Eagleton's Heathcliff and the Great Hunger: Studies in Irish Culture.