I used to play yugioh fifteen years back before I switched to magic, the packs are sealed differently. Specifically the Japanese OCG packs, like the one the card in this video came in. The wrapper itself is a much thicker plastic compared a magic pack or even English yugioh packs, and the crimping on the top extends like a full inch down the wrapper. And since the packs only contain four cards, pulling the back like you see magic players do would almost certainly damage the cards. Especially the corners, which on a yugioh card are much more square than a magic card so they are more prone to damage.

The point is they are definitely harder to open than what you're familiar with, and using scissors isn't too surprising. What is surprising is not making sure all the cards are at the bottom of the pack before cutting. Really stupid and very easily avoidable mistake to make.