Yeah... Marika has some very good points. I hate to admit it, but Yui needed that push. Bottling things up is just no way to go about things.
That really was a major flaw of her character- wanting so much to keep everything the same. It's a paralyzing feeling, not wanting to hurt anyone. Some characters or people even take that so far as to even harm themselves intentionally to protect others, like Hachiman Hikigaya in the first season and a half of RomCom SNAFU, intentionally sacrificing himself for the sake of club requests. Eventually, the people that grew to care about him had to tell him off for this self-destructive behavior.
And, now... the ball is rolling. The cat's out of the bag. Etc, etc...