There is a unconscious bias the imperial admirals have towards Yang Wenli.
Oberstein never met or fought against Yang before, hence he has no problems regarding him as the enemy. Even if that is not the case, he is fully capable of cutting off all emotions to deal with the matter objectively.
The same cannot be said of the admirals. Almost every admiral in the room fought against Yang. One of them even met him in person. They developed an utmost respect for Yang as a fellow commander and for his skills and leadership, even if he is the enemy. Their trust and respect for his moral and uncorrupt character goes so far as to believe Yang over Lennenkanpt, a guy on their team.
Oberstein was outnumbered in that meeting. Reuenthal quickly took control of the whole discussion and turned everyone against him and Lang, which is not difficult given the unanimous belief in Yang's innocence and shared hatred to Oberstein.
Ixiataaga
2021-02-23 04:49:02 +0000 UTC
Despite Mittermeyer's criticism, even he realizes how important Oberstein is to both Reinhard and the Empire. Knowing that fact is immensely frustrating to him, who values honor and valour above all else.