#2. Neither Kofi Kingston nor Seth Rollins was going to lose anyway

This is just the cold hard truth, which fans may more or less have to accept at this stage. Think about it from a realistic standpoint. Kofi Kingston and Seth Rollins both received major WrestleMania coronations.
While its not unheard of for these title reigns to end in a month or so, it's obvious that both of their wins were meant to represent a big change in WWE programming. Kofi Kingston made history as the first-ever African American WWE Champion, while Seth Rollins finally fulfilled his objective of bringing the Universal title back to RAW full time.
They're both the faces of their respective brands now and there was never going to be another double champion, especially after they just had one at WrestleMania. Thus, to protect both the WWE and Universal Champion, WWE decided that The Bar needed to interfere.