What is it called to attack a person then say something uplifting? Say a manager emailing the people under her in a way that to them feels degrading, and putting down. But at the end of the email its encouraging/uplifting type saying I know you are intelligent and capable people. 

So is there a name of this type of behavior to attack/degrade then at the end say something nice?
It sounds like a variant on the sandwich technique, which is advocated by some as the preferred way to deliver critical feedback to a person, like a student or employee. The sandwich technique can be defined as:


  ...offer[ing] a piece of negative feedback “sandwiched" between two positive
  ones, thus easing the blow of the critique.


Note that this technique is criticized, because people might not remember the crucial middle critical part of the message, because of the recency effect: our brains are hardwired to remember the first and last bits of a conversation whilst glossing over the middle part (source: WeQ).