They assume that an average ultra-high definition video requires 25 megabit per second. Their max theoretical capacity is 144Tbps so the math is: 144Tbps/25Mbit

They assume that an average ultra-high definition video requires 25 megabit per second. Their max theoretical capacity is 144Tbps so the math is: 144Tbps/25Mbits = 5760000 (5.76 million simultanious video streams). Their wording might be confusing but their math is correct.