Possibly, but that would be pretty damning. A license isn't something you should YOLO. If he is that laissez-faire about licensing the source code then what other important aspects of the project has he not given sufficient thought.

Misunderstanding or failing to predict the legal ramifications of choosing an extremely popular license is in no way an indicator of programming care or ability. They’re different sets of skills.

Also, something starts off as a nothingburger side project, so you make some decisions based on that. Then it develops a bit, and turns into something you care about and are able to turn into a business. What people want and expect changes over time, and a license on a codebase that is basically developed by one person, isn't a marriage.