I'm no expert but can share what little I know. An element of Japanese culture is about saving face so as not to cause embarrassment in public. The promoters of the show promised the fight. They want to keep their word but Gabi Garcia weighed in way over the set weight limit and her opponent thought it was disgraceful and turned down the fight. They all need to explain to the paying audience exactly what happened.
Garcia's opponent is a proud trainer who had agreed to fight Garcia at that weight limit. Since Garcia came in so far above the weight limit it was considered personally insulting to her opponent, to the Rizin promotion and to the fans. If Garcia wants to fight with Rizin again she must apologize, first to Rizin and to her opponent. Then, on her knees to the audience. There was some drama and some comedy in there as well.
Apparently everyone was satisfied that the apology was sincere. All of the body language says a lot too, in terms of her opponent shaking her hand but then staying away, the head of the promotion barely shaking her hand while walking away from her, nuances that speak volumes of what is sometimes referred to in Japan as harmony in public. Not saying this is everything that's going on here. A Japanese expert could explain far better and add to or contradict these details. Just trying to provide a slightly better understanding.