As you'll find if you dig into visa regulations in many countries, the definition of "business" (activities usually permitted on business visas or visa waiver programs) is typically a lot more detailed than just whether the company paying you is in or out of the jurisdiction.
This is why my employer's internal immigration processes, even for short-term visits like conferences or whatever, present you with a comprehensive list of different categories of activity you might be undertaking to determine whether you need a work permit or not. It's annoying, and our internal immigration systems are very, very much imperfect, but I can see how it came to be.
For example, in the US case, check out https://en.wikipedia.org/wiki/B_visa#Acceptable_and_prohibit.... The rules for B visas apply to ESTA as well. Journalism is explicitly prohibited on B visas.
This is why my employer's internal immigration processes, even for short-term visits like conferences or whatever, present you with a comprehensive list of different categories of activity you might be undertaking to determine whether you need a work permit or not. It's annoying, and our internal immigration systems are very, very much imperfect, but I can see how it came to be.