As the article shows, it is a bug in iTerm2. cat is just one program that could trigger it, the key thing is outputting attacker controlled text to the terminal when the attacker can control what files are present (ie unzipping a folder that includes a specific executable file at a well chosen location that gets triggered to run when the readme is output to the terminal)
Yes. It’s a Mac problem. That’s why Macs do the worst at pwn2own. It’s compounded by the fact that Mac users deny that there are problems in their beloved OS.
cat is a file concatenation utility. UNIX people know to view text files with more.