It's not a conspiracy theory. He brought in a lot of ex-RSL players and seems to favor them despite persistent mediocrity on the field. I don't think Wingert is playing poorly but the fact Grabavoy, KWS etc. are automatic starters is surreal. They're awful players, and the team hasn't won in 2 months. So his refusal to change things raises questions about his competence and his ability to control the dynamic in the dressing room. It also undermines the motivation of the other players when selections aren't being made on the basis of performance.
The results speak for themselves, performances are getting worse not better, and most people who follow the team are in agreement about where the problems are. Changes need to be made in the side and if Kreis doesn't have the ability to look beyond personal connections and do that, he needs to go.