There's a knot in the logic of those urging the presidential electors to deny Trump an electoral college majority. It comes between these two propositions:
1. The founders (wisely?) established the electoral college as a potential veto of the popular choice* in case the people (or state legislatures) voted in a demagogue.
2. The popular choice in this election was not a dangerous demagogue, as Hilary Clinton will end up with about 2.5 million more votes than Trump.
Thus, the electoral college should use its veto function to un-veto the popular choice rather than to countermand it.
The disconnect is between the electoral college as designed versus the electoral college as evolved. It was designed to be a deliberative body (or set of bodies, as each state's electors meet separately). It evolved into an inexact and unreliable mirror and intended rubber stamp of the popular choice. Like a human appendix, it serves no practical function except to rupture occasionally.
Ceding its original function as a deliberative organ with veto power, its only active function now (other than as a rubber stamp when the electoral vote ratifies the popular vote) is to serve as an arbitrary (and automatic) veto of the popular choice.
You can make a case for the veto function. You can't make a case for the body's current (dys)function.
So now, the pitch to the electoral college is to either veto itself, ratifying the popular vote by electing Hillary Clinton (which it won't do), or to revert to its original function and put up a third candidate (like, say, Mitt Romney). Of course, that would entail vetoing both candidates and essentially splitting the difference between winning the popular vote and the (designated/intended) electoral college vote.
Compromises are not known for their logical purity. 37 electoral votes for Mitt Romney is a very, very long shot, and if it happened the House would probably go for Trump in any case. Still, if something even more egregious about Trump comes out before December 19, or if in the interim he really does stand on 5th Avenue and shoot someone, the third candidate vote is a remote possibility.
* As articulated by Alexander Hamilton in Federalist Paper No. 68:
It was desirable that the sense of the people should operate in the choice of the person to whom so important a trust was to be confided. This end will be answered by committing the right of making it, not to any preestablished body, but to men chosen by the people for the special purpose, and at the particular conjuncture.It should be noted that the last paragraph quoted here does not say that the electoral college per se will prevent election of someone with "talents for low intrigue, and the little arts of popularity" -- rather that a national election will. But combined with the initial stated purpose of the college, and with a paragraph lauding the diffusion of the electoral college ("detached and divided") in the various states, the implication here is clear that the electoral college functions in concert with states serving as mutual checks on one another to protect against election of a demagogue.
It was equally desirable, that the immediate election should be made by men most capable of analyzing the qualities adapted to the station, and acting under circumstances favorable to deliberation, and to a judicious combination of all the reasons and inducements which were proper to govern their choice. A small number of persons, selected by their fellow-citizens from the general mass, will be most likely to possess the information and discernment requisite to such complicated investigations...
The process of election affords a moral certainty, that the office of President will never fall to the lot of any man who is not in an eminent degree endowed with the requisite qualifications. Talents for low intrigue, and the little arts of popularity, may alone suffice to elevate a man to the first honors in a single State; but it will require other talents, and a different kind of merit, to establish him in the esteem and confidence of the whole Union, or of so considerable a portion of it as would be necessary to make him a successful candidate for the distinguished office of President of the United States.