The answer is, that in m2m & zone a player is selected to be specifically doubleteamed (in this engine). So then the pbp notes the dt. Whereas, a FCP defense generally tries to force the ball to the sideline and trap to the sideline or other specific areas of the court. Then the panicked pass through the trap gets picked off. You're probably correct that some of the turnover messages should read: "[So & So] intercepts [what'shisface's] errant pass out of the trap."
Read coachvegas' comments in
this thread. He may be a bit combative and unpersuasive on being able to run FCP with a short bench, but there's no question he has some relevant experience.