To some it's about not being wrong. Many are invested in an idea and their entire public persona was built on that premise. So to pivot would mean admitting their prior assumptions were wrong.

To me it's very simple. If your data driven and not emotionally driven than one admits that the data they were looking at was flawed and now new data has been presented that counters their previous assumption. As such a pivot must happen if at the very least to a 'wait and see' appraoch or, once new data leads, to a new assumption. A perfect example of this, in my opinion, is Neil DeGrasse Tyson.

But what I mentioned above is contingent on the fact that the person is NOT emotionally driven. Thats not to say that they can not be correct in their assumptions but if not correct they will go down with their ship without regard to damage their public persona takes since in their mind everyone else is wrong and not their assumption.

Some are simply the right leaning equivalent of the emotional left. Sadly.