Should you ever resign? Masters do, IMs do, GMs do, World Champions do. So what do you think?
Well, my answer to that is no, I should not because I don't fall into any of the categories mentioned above & I like the endgame practice... not to mention that there's always the hope of a draw!
I think there is a distinction that was not made by the original thread poster.
The reason ( I'm not a GM or IM or any title for that matter - so I am not speaking for them ) I think GM's will resign after only a few points or even on equal points but a bad position - is that they understand that their opponent is also highly rated and probably prepared for the match and is ready to calculate the winning lines necessary to finish out the position.
Conversely, I do not think the original thread poster nor many players on Chess.com ( all highly rated players aside ) can make that claim - that they are well prepared for every match, that they calculate all of the lines in detail many, many moves ahead, that they are experienced in high-level tournament play. That is not to say we don't try to play good chess - I know I do, but I am not arrogant enough to put myself on the GM level right now - so for players such as myself & other learners of the chess game, it may be instructional to see the various moves associated with a king vs army endgame.
Then there is the issue of playing for money & publicity & rating & status & performance that I would assume factor into GM play - something that I can for sure say I have not experienced given that I am not a professional chess player right now.
So to close I think there is a difference between trying to compare GMs and many players on Chess.com ( all GMs, IMs, FMs, CMs, whether women or men, aside ) I am talking about the average player - they may actually gain valuable experience from sticking out a match - no matter what the losing position looks like.