Before Timsort, I knew of Tim some 20 years ago from the ranking and online forum of SPOJ[1], a Polish competitive programming website where he always seemed to top the speed leaderboards with unorthodox usage of Python.
He's exceptionally talented and original, and that sort of nonsense doesn't go well with a bureaucracy.
Not all, but some exceptionally talented people might be hard to work with as well, so that anecdote doesn't give much information---you may well have claimed such observation as a generality and argued in the other way.
You're right, generalizations are difficult, and I can't give a second hand summary of how the younger me perceived Tim's posts. One thing I remember is that he didn't give off the dogmatic stubbornness or indifference to the reasoning of others that seems to be correlated with the difficulty in working with smart people.
He's exceptionally talented and original, and that sort of nonsense doesn't go well with a bureaucracy.
[1] https://spoj.com