Hello there, author of the article here. You bring up a great point: This is a case in which the stakes are high and some things I said in the article don't apply.

In this case I would suggest that there should have been a lead or senior overseeing your coworker who was responsible for the quality of their code. This person should have already demonstrated good judgment in code quality, should have some people skill and backbone in dealing with folks who take code reviews personally and have the authority of the team to make the final decision on whether code gets integrated into your mainline branch.

If you're not that person then there's not much that you can do about a coworker's bad code other than push the team towards a stronger structure and process to protect it from bad code.