Kurt is the token "mediocre" person. He's not smart, his ability with the sword is decent but not great, and the only thing he has going is being the eldest son. The father is an extremely conservative person ( or a coward also works) that would rather let his territory fall to ruin than let something change under his rule.
As such, when Wendelin starts rising in capital, they becomes more and more embittered. The thing both him and his father don't see is that Wend would never stay permanently on their territory. They're too small to notice that Wend is already much bigger than them.
The Baumesteirs are a small, petty household with a small, petty mindset. In previous chapters, it is show the margrave (the superior of the Baumeisters) and his other subordinate houses look down on the Baumesteirs, and it is with good reason. They're not politically savvy to make allies, and they're not successful to get people to acknowledge them. They're poor, and they're reclusive. So outside of the taxes they send to the margrave, they might as well don't exist.