The "casting out of a demon" must refer to an actual change.
The man's blindness may refer to his inability to see truth;
that he can now see may refer to his new allegiance.
That he can now speak may point to his new role,
as an ambassador for the embryo movement.
The authorities are unconvinced;
saw his message as dangerous and of the devil.
Perhaps a threat to them or their way of living;
the dominant role of a politicised priesthood;
the subservience of religion to Rome.
Perhaps forseeing the horror of war
and the danger of armed rebellion.
This was the threatening demon!
Perhaps they were right for all that followed,
only thirty or so years after Jesus died,
was there in an embryo, initial, form.
Were the gatherings that met with Jesus
seen as of a revolutionary nature?
Did authority see violence ahead,
something they were desperate
to prevent?