Bravo, Dario! I have never liked the invocation of "pseudo-work", either.
Another argument goes thusly: All agree that the W-E th. can be applied to
a point particle. Well, each particle making up the object (car or person)
must have work done on it by a force if it is to accelerate. For most of
the particles this force is due to its neighbor particles . . . this chain
of forces must lead to that of an external agent - the internal forces
cancel to zero in their net effect. Each of these many forces does REAL WORK!