You know I agree with you maybee that there are so many things wrong with this movie. The Fixer Upper song was painful to watch. A lot of people who I have seen argue in favour of that particular scene, saying it's obvious that the trolls misunderstood or whatever, are having to dig deep in order to prove that. Kids watching this movie are not going to analyse it like that; they are going to accept it on face value and sing the words around their houses.
You can fix this fixer-upper
Up with a little bit of love!
Kristoff: ENOUGH! She is engaged to someone else, okay?!
Cliff: So she's a bit of a fixer-upper,
Male Troll 4: That's a minor thing.
Male Troll 5: Her quote 'engagement' is a flex arrangement.
Troll Child: And by the way I don't see no ring!
People make bad choices if they're mad,
Or scared, or stressed.
Throw a little love their way.
And you'll bring out their best.
None of those messages are positive on face value.
I also agree with you maybee that earlier they were so against a quick marriage, and that's an awesome message given how quickly everyone generally gets married in Disney movies, but then suddenly they are promoting it as being a fantastic idea again with a peppy song.