I think that this question, in its very statement, has to be regarded as a matter of opinion.
Specifically, as the question asks about 'an underlying sentiment'.
What sentiment underlies the sentiments being expressed has to be a matter of conjecture and personal perception. Or, in other words, it has to be a matter of suspicion.
Suspicion of insincerity is what is being conjectured.
Personally, I saw massive respect being shown for someone who had - voluntarily for a number of years - performed a valuable service to a community.
Personally, I saw massive sympathy being shown towards someone who was prepared to resign from a position, of considerable honour and respect within the community, on a matter of principle.
Personally, I saw massive empathy being shown towards someone who acted in conscience, choosing to maintain their principles rather than do what they, themselves, felt to be wrong.
That response was, indeed, as the OP above states : extraordinary. Out of the ordinary. Beyond what is - ordinarily - witnessed.
These are my own perceptions and these are my own impressions.
I do not, personally, suspect there were ulterior motives or underlying sentiments.
Because none of these were being expressed.
What was being expressed was a vote. That vote was a response : a response to someone who acted in conscience. And did what they felt they had to do.
Such actions are always impressive. The actual issue lies in the background. It might have been any issue. We can tell that that person would have responded in exactly the same way, whatever the particular issue might have been. What comes to the fore, in cases such as these, is integrity.
I believe the extraordinary response was a response towards conscientious integrity. And I saw, myself, no hint of hypocrisy and no hint of insincere, underlying sentimentinsincerity whatsoever.