Yes, literally, the dictionary meaning of a "penny pincher" is one who does not want to part with his pennies.
The author of the article, on the other hand, seems to call people "penny pinchers" if they do not adopt rules of thumb but instead painstakingly analyze all alternatives. Sure, paralysis by analysis can be bad or there is nothing wrong with focusing one's cognitive energies sparingly etc, but there is very little in the article about penny pinching.
You preferences may say "it is more important for me to save seven bucks in this context." That does not compel other people to enjoy your preferences.
In my life, I have been in groups where if a few people consumed some relatively more expensive food or drinks, they are responsible enough to take care of that.
Also, when you go out with a large group, you do tip the wait staff generously, right?