I've got two friends there, a civil servant and a contractor, and I've heard no such thing. That doesn't mean it isn't true, but I'm curious whether there's any data to back this up. You'd have to be careful looking at that data, too: a lot of people are retiring from NASA simply because they're old.
Nothing that's happened to NASA lately is a new phenomenon.
Today, the President signed the Consolidated Appropriations Act of 2017, which funds the U.S. government for the remainder of the fiscal year. NASA received $19.65 billion—its best budget since 2010—and the Planetary Science Division saw its budget increase to $1.846 billion—its best budget in more than ten years.
http://www.planetary.org/blogs/casey-dreier/2017/fy2017-plan...
NASA still does quite a bit of science work though, so I wouldn't count them out entirely. Administrations come and go. Sometimes you just gotta keep your head down and keep doing your job until someone better is voted in.
I think what the people actually working there try to do (as it can be seen here) is find a way to fit what they have already done, with what the new mission statement is, so that they won't have to scrap everything they have done, only the limited amount. That's good is some senses (less wasted work), but the result is then usually not the most fitting solution.
Public servants get demotivated and set to mediocrity. Hired cattle gets demotivated and try to get out.
Only managers and middle managers are driven by the ego boost coming from "changing things".