Was it the default software center? From my memory of the video, he tried to install Steam through the Ubuntu Software Center at first which failed, and then he found a guide that mentioned using sudo apt install steam to which apt made him type Yes, do as I say to confirm the (unfortunate) set of actions it was going to perform.

While I still don’t blame Linus, a more apt (ha!) comparison would probably be trying to do something over the CLI instead of through the Microsoft Store.