@tonie: Being that direct about would be failure as nobles, not to mention potentially suicidal seeing as they're in the 'enemy' territory. (Hell, prince here was like "I DO sure hope they do something, that way I CAN MURDER ALL OF THEM")
Also, unless the flavor itself is unanimously 'bad', the prince can always counter them with "Oh, can YOUR chefs do something better than this with low quality meat?" (since they already know the meat spoiled, admitting it has no demerit to him)
If they accept, he can make them prove it (and likely to fail), and if they don't, they're the one shamed.
One other option, given how this is a shoujo and all the things in ch 12, is that their own leader like the hamburg steak because he had it with Marie in the past.
Something like the young prince snuck out into town, get befriended by Marie and at some point visit her home and get to taste this.
(Alternative option is he TOO was like Marie in that they have royal blood without being recognized as such, either because illegitimate child or hidden to avoid political schemes)
Obviously her being a commoner mean he can't make her a queen, but even a mistress of the king would still be a large improvement to her life (in his view)
But then turns out she is a princess so yay he just needed to wait until she's of-age and court her after her social debut.
But that plan got thrown out the window because mr bloody prince murdered the Cloyans, but hey there's rumors that the princess is alive.
So he plotted (or get stopped from rushing in), and this festival is a good excuse for him to visit Cloyan and search for her as any.
In ch 12 we know the Western Empire is looking for her, and the amount of escorts they sent is like they're escorting a royal family member.
Anyway, if their own prince like it, them criticizing it would be suicidal in a different direction.
