What struck me about Brooks' statement was the idea of 'mental maps' and 'terms that organize thinking'. Certainly there's no challenge to the idea of 'change is hard' -- this is accepted routinely and said often. But as a root cause, I'd never really thought of the organized thought thing.
Asking (or imposing on) someone to reorganize their mental map of values and beliefs is no small matter. As a matter of professional necessity, many are able to separate their personal map from the new/changed/different map given to them by their job/profession/organization/project -- but many are not, and they are left deeply conflicted and unhappy (perhaps, unproductive as well) ... or they leave.
Sometimes worse than re-mapping, change may trigger fear losing what we've got. To wit: it was too hard to get here to lose it now. (See: Prospect theory)
And, unfortunately fear is always an easy sell, possibly even layering on some elements of paranoia, but always driving resistance and defensive actions.
In short, change is hard!