[AskewEgret]

When you are new, you should be given a lot of leeway to ask questions. So, perhaps you should set aside potential motives and use these rejections as opportunities to ask questions.

Something along the lines of: "I've worked at a lot of places, and none of them have ever done the on-boarding process perfectly. One thing I try to do is to document some of the problems encountered as well as the solutions or mitigating factors. It will definitely help me become a productive member of the existing team with the existing culture, but all future employees will benefit as well. Can you help me understand the thought process that went into this rejection, what I missed, what I did wrong, etc?"

You would hope that management recognizes the long-term benefit of such an exercise and would support you. It also places a fair burden on the rejecting engineer to explain him or herself.