Earlier quoted context omitted.
It depends on where you live, at least in Europe most people would find the word inappropriate. For us here "disobedience" or something alike would be a better term.
Insubordination is an english word, and it is written into employment law as grounds for immediate dismissal. "Disobedience" isn't. Basically, if you take a paid job, you subordinate yourself to your boss.
We are talking about a Danish person hired by an European company. I fail to see the point of your comment.