Tanthalas, I really think you're missing the big picture here. If this had been an adult comedy, and there were previous allusions to there being an issue with the relationship, and then other characters continued to rag on them for it after, a scene like this could have been a funny payoff.
However, it's a scene that has nothing to do with anything, that was forced into the middle of a children's movie, regarding characters that could have just been 18+19 and there would never have been a reason to address this or bring it up at all.
It's weird bro.
There's a time and place for everything... but not now.