I agree. I'm friends with so many people from high school and other times and places in my life on facebook, a few years ago I talked to my highschool bf on the phone for HOURS and caught up with him, and I actually stayed in touch with my ESFJ ex for a long time and tried to be friends with him for years, and in a weird sort of way even felt RESPONSIBLE for him because he has emotional problems.
No, I don't think ENFPs are door slammers. Even with people I'm not especially close to I can get over being mad and forgive them, unless they just keep violating my values or are just particularly repellent to me.
I do think we can seem to attach quickly since we'll be so enthusiastic about people whom we like, and I can't say I've detached quickly from someone I actually truly cared about...however, we do have a way of moving on with our lives, for the most part, if something begins to seem unhealthy or isn't working anymore.
I actually was very dedicated to trying to make my relationship with my ESFJ ex work, but the issues were insurmountable because he wouldn't stay in therapy. He might perceive me as the person who 'detached' but that's only because he won't take responsibility for doing something about his behavioral problems.