Every? Scanning them quickly, I count less than 20 different countries.
A better question would be “why does Wikipedia explicitly list the country of origin for anti-virus software?” (It doesn’t for word processors (https://en.wikipedia.org/wiki/Comparison_of_word_processors) or file archivers (https://en.wikipedia.org/wiki/Comparison_of_file_archivers), for example)
Answer is that anti-virus software sits deep into your OS, by necessity, reads all your data, and typically also tries to read all your network traffic. That makes it an ideal place for intelligence agencies to put their software, and it likely is easier for country X’s intelligence agency to coerce a company in X to help doing that.
The iOS category on that page is interesting, too, by the way: a discontinued on demand file scanner and two tools that offer “anti-theft” and “backup”, both of which ship standard with iOS.
