@sirflimflam
As I stated in my previous comment, I kind of understand how all that applies to Lefille's situation. She obviously has the social and religious pressure of "the oracle" hanging over her head. Add to that the child appearance and it's quite obvious her opinion will be hard to express and even harder to have people actually hear it.
Felmina is definitely another matter. There is no oracle about her, she's an adult and she has demonstrated in previous chapters how she still has some pretty strong confidence when not dealing with Suimei. She's definitely able to reject the "invitation" in a way that makes it clear she's not interested, and potentially that Lefille is not interested either. She's tried to intervene once before being invited and from there she just let Suimei start a ... measuring contest with the hero. The way I see it is not so much Suimei doing something wrong. Just the author letting Felmina fall in the background when she should have had enough strength to stand for herself as she started doing for Lefille. The image of "the hero" should not have fazed her that much knowing Suimei's accomplishments. It would be like being impressed by a count's bragging when she has the king standing by her side. For god(dess)'s sake, she herself summoned another "hero" and Suimei is more impressive than him. She knows heroes are great, but not necessarily the pinnacle of authority, strength or magic. And she's used to navigate the upper echelon of society, having been the court mage of a king herself. What I'm blaming is the author erasing all of Felmina's great traits in favor of "Suimei is going to grind that hero's arrogance to dust". And that would have also been better for Suimei who's - supposedly - trying to keep low-profile.
It would have been better if she had opposed that so-called "hero", then Suimei could have stepped in had the "hero" tried to use violence. Instead we're back to the common trope where team members are useless and the MC has to solve everything.