Yes it is. You can be a pedantic a-hole all you want, but “hacking” includes phishing, social engineering and pretty much any other form of access control circumvention to the general public.
Edit:
Also from the article itself
A 'readme' file in the archive states that the threat actor used an exposed GitHub token to access the company's repositories and steal the data.
Exposed GitHub token is very likely someone messed up and either exposed a token or was victim to an attack that could pull the token. Those are not uncommon and have happened to a lot of companies.