Get your message crossed while talking about best practice, process, and methodology. No matter what you feel about certain colleague, don't complain about a person or second-guess anyone's intention. Talk about acts and results only.
Don't make this about something you don't like, as a matter of fact, it's not something right for your team, your boss, and the project.
What happened happened, don't make it too hard for yourself.
Have a good weekend!